diff --git a/src/cmd/extrinsics/transcode/decode.rs b/src/cmd/extrinsics/transcode/decode.rs
index f22f061c8bec4f36b39645feaea4f657146a43c7..1654a74488c2b6c33907adb0f18c94445e297595 100644
--- a/src/cmd/extrinsics/transcode/decode.rs
+++ b/src/cmd/extrinsics/transcode/decode.rs
@@ -91,18 +91,12 @@ impl<'a> Decoder<'a> {
             anyhow::anyhow!("Failed to find type with id '{}'", type_id)
         })?;
 
-        if *ty.type_def() == TypeDef::Primitive(TypeDefPrimitive::U8) {
-            let mut bytes = vec![0u8; len];
-            input.read(&mut bytes)?;
-            Ok(Value::Bytes(bytes.into()))
-        } else {
-            let mut elems = Vec::new();
-            while elems.len() < len as usize {
-                let elem = self.decode_type(type_id, ty, input)?;
-                elems.push(elem)
-            }
-            Ok(Value::Seq(elems.into()))
+        let mut elems = Vec::new();
+        while elems.len() < len as usize {
+            let elem = self.decode_type(type_id, ty, input)?;
+            elems.push(elem)
         }
+        Ok(Value::Seq(elems.into()))
     }
 
     fn decode_type(
diff --git a/src/cmd/extrinsics/transcode/encode.rs b/src/cmd/extrinsics/transcode/encode.rs
index aa7d5c22273b8e3bc30b50ddf4f280373f282f66..86fdc833fac9ab21f8d367f73b76cb6f337031e3 100644
--- a/src/cmd/extrinsics/transcode/encode.rs
+++ b/src/cmd/extrinsics/transcode/encode.rs
@@ -248,11 +248,11 @@ impl<'a> Encoder<'a> {
                     self.encode(ty.id(), value, output)?;
                 }
             }
-            Value::Bytes(bytes) => {
+            Value::Hex(hex) => {
                 if encode_len {
-                    Compact(bytes.bytes().len() as u32).encode_to(output);
+                    Compact(hex.bytes().len() as u32).encode_to(output);
                 }
-                for byte in bytes.bytes() {
+                for byte in hex.bytes() {
                     output.push_byte(*byte);
                 }
             }
@@ -410,7 +410,7 @@ impl<'a> Encoder<'a> {
 
 fn uint_from_value<T>(value: &Value, expected: &str) -> Result<T>
 where
-    T: TryFrom<u128> + FromStr,
+    T: TryFrom<u128> + TryFromHex + FromStr,
     <T as TryFrom<u128>>::Error: Error + Send + Sync + 'static,
     <T as FromStr>::Err: Error + Send + Sync + 'static,
 {
@@ -424,6 +424,10 @@ where
             let uint = T::from_str(&sanitized)?;
             Ok(uint)
         }
+        Value::Hex(hex) => {
+            let uint = T::try_from_hex(hex.as_str())?;
+            Ok(uint)
+        }
         _ => {
             Err(anyhow::anyhow!(
                 "Expected a {} or a String value, got {}",
@@ -436,7 +440,7 @@ where
 
 fn encode_uint<T, O>(value: &Value, expected: &str, output: &mut O) -> Result<()>
 where
-    T: TryFrom<u128> + FromStr + Encode,
+    T: TryFrom<u128> + TryFromHex + FromStr + Encode,
     <T as TryFrom<u128>>::Error: Error + Send + Sync + 'static,
     <T as FromStr>::Err: Error + Send + Sync + 'static,
     O: Output,
@@ -479,3 +483,21 @@ where
     int.encode_to(output);
     Ok(())
 }
+
+/// Attempt to instantiate a type from its little-endian bytes representation.
+pub trait TryFromHex: Sized {
+    /// Create a new instance from the little-endian bytes representation.
+    fn try_from_hex(hex: &str) -> Result<Self>;
+}
+
+macro_rules! impl_try_from_hex {
+    ( $($ty:ident),* ) => { $(
+        impl TryFromHex for $ty {
+            fn try_from_hex(hex: &str) -> Result<Self> {
+                $ty::from_str_radix(hex, 16).map_err(Into::into)
+            }
+        }
+    )* }
+}
+
+impl_try_from_hex!(u8, u16, u32, u64, u128);
diff --git a/src/cmd/extrinsics/transcode/env_types.rs b/src/cmd/extrinsics/transcode/env_types.rs
index 7e526569246d8b1fd1f2fe9fc8c83983f4811d03..7ecaad99a845fb5b4f422525891e9f385b7620f3 100644
--- a/src/cmd/extrinsics/transcode/env_types.rs
+++ b/src/cmd/extrinsics/transcode/env_types.rs
@@ -161,9 +161,12 @@ impl CustomTypeTranscoder for AccountId {
                     )
                 })?
             }
-            Value::Bytes(bytes) => {
-                AccountId32::try_from(bytes.bytes()).map_err(|_| {
-                    anyhow::anyhow!("Error converting bytes `{:?}` to AccountId", bytes)
+            Value::Hex(hex) => {
+                AccountId32::try_from(hex.bytes()).map_err(|_| {
+                    anyhow::anyhow!(
+                        "Error converting hex bytes `{:?}` to AccountId",
+                        hex.bytes()
+                    )
                 })?
             }
             _ => {
diff --git a/src/cmd/extrinsics/transcode/mod.rs b/src/cmd/extrinsics/transcode/mod.rs
index daf95b16cc173511e1c030e20510aa34dacabce6..bac8be4260985113d8af744690589d14b38cc28f 100644
--- a/src/cmd/extrinsics/transcode/mod.rs
+++ b/src/cmd/extrinsics/transcode/mod.rs
@@ -398,6 +398,22 @@ mod tests {
             pub fn primitive_vec_args(&self, args: Vec<u32>) {
                 let _ = args;
             }
+
+            #[ink(message)]
+            pub fn uint_args(
+                &self,
+                _u8: u8,
+                _u16: u16,
+                _u32: u32,
+                _u64: u64,
+                _u128: u128,
+            ) {
+            }
+
+            #[ink(message)]
+            pub fn uint_array_args(&self, arr: [u8; 4]) {
+                let _ = arr;
+            }
         }
     }
 
@@ -489,6 +505,52 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn encode_uint_hex_literals() -> Result<()> {
+        let metadata = generate_metadata();
+        let transcoder = ContractMessageTranscoder::new(&metadata);
+
+        let encoded = transcoder.encode(
+            "uint_args",
+            &[
+                "0x00",
+                "0xDEAD",
+                "0xDEADBEEF",
+                "0xDEADBEEF12345678",
+                "0xDEADBEEF0123456789ABCDEF01234567",
+            ],
+        )?;
+
+        // encoded args follow the 4 byte selector
+        let encoded_args = &encoded[4..];
+
+        let expected = (
+            0x00u8,
+            0xDEADu16,
+            0xDEADBEEFu32,
+            0xDEADBEEF12345678u64,
+            0xDEADBEEF0123456789ABCDEF01234567u128,
+        );
+        assert_eq!(expected.encode(), encoded_args);
+        Ok(())
+    }
+
+    #[test]
+    fn encode_uint_arr_hex_literals() -> Result<()> {
+        let metadata = generate_metadata();
+        let transcoder = ContractMessageTranscoder::new(&metadata);
+
+        let encoded =
+            transcoder.encode("uint_array_args", &["[0xDE, 0xAD, 0xBE, 0xEF]"])?;
+
+        // encoded args follow the 4 byte selector
+        let encoded_args = &encoded[4..];
+
+        let expected: [u8; 4] = [0xDE, 0xAD, 0xBE, 0xEF];
+        assert_eq!(expected.encode(), encoded_args);
+        Ok(())
+    }
+
     #[test]
     fn decode_primitive_return() -> Result<()> {
         let metadata = generate_metadata();
diff --git a/src/cmd/extrinsics/transcode/scon/display.rs b/src/cmd/extrinsics/transcode/scon/display.rs
index 8ccaf8e39ef4a55fe19bc9e3463516ee9fbf15b3..499634bf4b91ac6bed342dbc76368d12de3678a7 100644
--- a/src/cmd/extrinsics/transcode/scon/display.rs
+++ b/src/cmd/extrinsics/transcode/scon/display.rs
@@ -15,7 +15,7 @@
 // along with cargo-contract.  If not, see <http://www.gnu.org/licenses/>.
 
 use super::{
-    Bytes,
+    Hex,
     Map,
     Seq,
     Tuple,
@@ -43,7 +43,7 @@ impl<'a> Debug for DisplayValue<'a> {
             Value::Tuple(tuple) => <DisplayTuple as Debug>::fmt(&DisplayTuple(tuple), f),
             Value::String(string) => <String as Display>::fmt(string, f),
             Value::Seq(seq) => <DisplaySeq as Debug>::fmt(&DisplaySeq(seq), f),
-            Value::Bytes(bytes) => <Bytes as Debug>::fmt(bytes, f),
+            Value::Hex(hex) => <Hex as Debug>::fmt(hex, f),
             Value::Literal(literal) => <String as Display>::fmt(literal, f),
             Value::Unit => write!(f, "()"),
         }
@@ -107,13 +107,13 @@ impl<'a> Debug for DisplaySeq<'a> {
     }
 }
 
-impl Debug for Bytes {
+impl Debug for Hex {
     fn fmt(&self, f: &mut Formatter<'_>) -> Result {
         write!(f, "{:#x}", self)
     }
 }
 
-impl LowerHex for Bytes {
+impl LowerHex for Hex {
     fn fmt(&self, f: &mut Formatter<'_>) -> Result {
         if f.alternate() {
             write!(f, "0x{}", hex::encode(&self.bytes))
diff --git a/src/cmd/extrinsics/transcode/scon/mod.rs b/src/cmd/extrinsics/transcode/scon/mod.rs
index 66b45ca258cc9018f4bc986c0d99b3b45e1b0bff..85882c52886958a49265ece48158cc6cf9f64250 100644
--- a/src/cmd/extrinsics/transcode/scon/mod.rs
+++ b/src/cmd/extrinsics/transcode/scon/mod.rs
@@ -21,6 +21,7 @@ mod parse;
 
 use indexmap::IndexMap;
 
+use crate::util;
 use std::{
     cmp::{
         Eq,
@@ -35,6 +36,7 @@ use std::{
         Index,
         IndexMut,
     },
+    str::FromStr,
 };
 
 pub use self::parse::parse_value;
@@ -49,7 +51,7 @@ pub enum Value {
     Tuple(Tuple),
     String(String),
     Seq(Seq),
-    Bytes(Bytes),
+    Hex(Hex),
     Literal(String),
     Unit,
 }
@@ -199,20 +201,24 @@ impl Seq {
 }
 
 #[derive(Clone, Eq, Hash, Ord, PartialEq, PartialOrd)]
-pub struct Bytes {
+pub struct Hex {
+    s: String,
     bytes: Vec<u8>,
 }
 
-impl From<Vec<u8>> for Bytes {
-    fn from(bytes: Vec<u8>) -> Self {
-        Self { bytes }
+impl FromStr for Hex {
+    type Err = hex::FromHexError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let s = s.trim_start_matches("0x").to_string();
+        let bytes = util::decode_hex(&s)?;
+        Ok(Self { s, bytes })
     }
 }
 
-impl Bytes {
-    pub fn from_hex_string(s: &str) -> Result<Self, hex::FromHexError> {
-        let bytes = crate::util::decode_hex(s)?;
-        Ok(Self { bytes })
+impl Hex {
+    pub fn as_str(&self) -> &str {
+        &self.s
     }
 
     pub fn bytes(&self) -> &[u8] {
diff --git a/src/cmd/extrinsics/transcode/scon/parse.rs b/src/cmd/extrinsics/transcode/scon/parse.rs
index 2e6ae484258d25ddb6e2d83f6a2ba909b3ae236a..1df831667f205bbfaeed56b7738367fe765e3d8b 100644
--- a/src/cmd/extrinsics/transcode/scon/parse.rs
+++ b/src/cmd/extrinsics/transcode/scon/parse.rs
@@ -15,7 +15,7 @@
 // along with cargo-contract.  If not, see <http://www.gnu.org/licenses/>.
 
 use super::{
-    Bytes,
+    Hex,
     Map,
     Tuple,
     Value,
@@ -53,6 +53,7 @@ use nom_supreme::{
     error::ErrorTree,
     ParserExt,
 };
+use std::str::FromStr as _;
 
 /// Attempt to parse a SCON value
 pub fn parse_value(input: &str) -> anyhow::Result<Value> {
@@ -64,7 +65,7 @@ pub fn parse_value(input: &str) -> anyhow::Result<Value> {
 fn scon_value(input: &str) -> IResult<&str, Value, ErrorTree<&str>> {
     ws(alt((
         scon_unit,
-        scon_bytes,
+        scon_hex,
         scon_seq,
         scon_tuple,
         scon_map,
@@ -221,12 +222,12 @@ fn scon_map(input: &str) -> IResult<&str, Value, ErrorTree<&str>> {
         .parse(input)
 }
 
-fn scon_bytes(input: &str) -> IResult<&str, Value, ErrorTree<&str>> {
+fn scon_hex(input: &str) -> IResult<&str, Value, ErrorTree<&str>> {
     tag("0x")
         .precedes(hex_digit1)
         .map_res::<_, _, hex::FromHexError>(|byte_str| {
-            let bytes = Bytes::from_hex_string(byte_str)?;
-            Ok(Value::Bytes(bytes))
+            let hex = Hex::from_str(byte_str)?;
+            Ok(Value::Hex(hex))
         })
         .parse(input)
 }
@@ -602,10 +603,13 @@ mod tests {
 
     #[test]
     fn test_bytes() {
-        assert_scon_value(r#"0x0000"#, Value::Bytes(vec![0u8; 2].into()));
+        assert_scon_value("0x0000", Value::Hex(Hex::from_str("0x0000").unwrap()));
         assert_scon_value(
-            r#"0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF"#,
-            Value::Bytes(vec![255u8; 23].into()),
+            "0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF",
+            Value::Hex(
+                Hex::from_str("0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF")
+                    .unwrap(),
+            ),
         );
     }
 }
diff --git a/src/cmd/extrinsics/transcode/transcoder.rs b/src/cmd/extrinsics/transcode/transcoder.rs
index 591266de6542103bdb7c8de979ded1a3689e6d8f..c575c442ac74022b30a1d6b6bb4435f0ca6dd3e0 100644
--- a/src/cmd/extrinsics/transcode/transcoder.rs
+++ b/src/cmd/extrinsics/transcode/transcoder.rs
@@ -133,6 +133,7 @@ mod tests {
     use super::{
         super::scon::{
             self,
+            Hex,
             Map,
             Seq,
             Tuple,
@@ -140,16 +141,14 @@ mod tests {
         },
         *,
     };
-    use crate::cmd::extrinsics::{
-        transcode,
-        transcode::scon::Bytes,
-    };
+    use crate::cmd::extrinsics::transcode;
     use scale::Encode;
     use scale_info::{
         MetaType,
         Registry,
         TypeInfo,
     };
+    use std::str::FromStr;
 
     fn registry_with_type<T>() -> Result<(PortableRegistry, u32)>
     where
@@ -264,15 +263,31 @@ mod tests {
     fn transcode_byte_array() -> Result<()> {
         transcode_roundtrip::<[u8; 2]>(
             r#"0x0000"#,
-            Value::Bytes(vec![0x00, 0x00].into()),
+            Value::Seq(vec![Value::UInt(0x00), Value::UInt(0x00)].into()),
         )?;
         transcode_roundtrip::<[u8; 4]>(
             r#"0xDEADBEEF"#,
-            Value::Bytes(vec![0xDE, 0xAD, 0xBE, 0xEF].into()),
+            Value::Seq(
+                vec![
+                    Value::UInt(0xDE),
+                    Value::UInt(0xAD),
+                    Value::UInt(0xBE),
+                    Value::UInt(0xEF),
+                ]
+                .into(),
+            ),
         )?;
         transcode_roundtrip::<[u8; 4]>(
             r#"0xdeadbeef"#,
-            Value::Bytes(vec![0xDE, 0xAD, 0xBE, 0xEF].into()),
+            Value::Seq(
+                vec![
+                    Value::UInt(0xDE),
+                    Value::UInt(0xAD),
+                    Value::UInt(0xBE),
+                    Value::UInt(0xEF),
+                ]
+                .into(),
+            ),
         )
     }
 
@@ -321,7 +336,15 @@ mod tests {
                 vec![
                     Value::UInt(1),
                     Value::String("ink!".to_string()),
-                    Value::Bytes(vec![0xDE, 0xAD, 0xBE, 0xEF].into()),
+                    Value::Seq(
+                        vec![
+                            Value::UInt(0xDE),
+                            Value::UInt(0xAD),
+                            Value::UInt(0xBE),
+                            Value::UInt(0xEF),
+                        ]
+                        .into(),
+                    ),
                 ],
             )),
         )
@@ -350,7 +373,15 @@ mod tests {
                     ),
                     (
                         Value::String("c".to_string()),
-                        Value::Bytes(vec![0xDE, 0xAD, 0xBE, 0xEF].into()),
+                        Value::Seq(
+                            vec![
+                                Value::UInt(0xDE),
+                                Value::UInt(0xAD),
+                                Value::UInt(0xBE),
+                                Value::UInt(0xEF),
+                            ]
+                            .into(),
+                        ),
                     ),
                     (
                         Value::String("d".to_string()),
@@ -364,7 +395,15 @@ mod tests {
                                     ),
                                     (
                                         Value::String("c".to_string()),
-                                        Value::Bytes(vec![0xDE, 0xAD, 0xBE, 0xEF].into()),
+                                        Value::Seq(
+                                            vec![
+                                                Value::UInt(0xDE),
+                                                Value::UInt(0xAD),
+                                                Value::UInt(0xBE),
+                                                Value::UInt(0xEF),
+                                            ]
+                                            .into(),
+                                        ),
                                     ),
                                     (
                                         Value::String("d".to_string()),
@@ -439,7 +478,15 @@ mod tests {
                     ),
                     (
                         Value::String("c".to_string()),
-                        Value::Bytes(vec![0xDE, 0xAD, 0xBE, 0xEF].into()),
+                        Value::Seq(
+                            vec![
+                                Value::UInt(0xDE),
+                                Value::UInt(0xAD),
+                                Value::UInt(0xBE),
+                                Value::UInt(0xEF),
+                            ]
+                            .into(),
+                        ),
                     ),
                 ]
                 .into_iter()
@@ -461,7 +508,15 @@ mod tests {
                 vec![
                     Value::UInt(1),
                     Value::String("ink!".to_string()),
-                    Value::Bytes(vec![0xDE, 0xAD, 0xBE, 0xEF].into()),
+                    Value::Seq(
+                        vec![
+                            Value::UInt(0xDE),
+                            Value::UInt(0xAD),
+                            Value::UInt(0xBE),
+                            Value::UInt(0xEF),
+                        ]
+                        .into(),
+                    ),
                 ],
             )),
         )
@@ -477,7 +532,15 @@ mod tests {
             r#"0xDEADBEEF"#,
             Value::Tuple(Tuple::new(
                 Some("S"),
-                vec![Value::Bytes(vec![0xDE, 0xAD, 0xBE, 0xEF].into())],
+                vec![Value::Seq(
+                    vec![
+                        Value::UInt(0xDE),
+                        Value::UInt(0xAD),
+                        Value::UInt(0xBE),
+                        Value::UInt(0xEF),
+                    ]
+                    .into(),
+                )],
             )),
         )
     }
@@ -488,7 +551,15 @@ mod tests {
             r#"0xDEADBEEF"#,
             Value::Tuple(Tuple::new(
                 None,
-                vec![Value::Bytes(vec![0xDE, 0xAD, 0xBE, 0xEF].into())],
+                vec![Value::Seq(
+                    vec![
+                        Value::UInt(0xDE),
+                        Value::UInt(0xAD),
+                        Value::UInt(0xBE),
+                        Value::UInt(0xEF),
+                    ]
+                    .into(),
+                )],
             )),
         )
     }
@@ -611,6 +682,12 @@ mod tests {
 
     #[test]
     fn transcode_account_id_custom_ss58_encoding_seq() -> Result<()> {
+        let hex_to_bytes = |hex: &str| -> Result<Value> {
+            let hex = Hex::from_str(hex)?;
+            let values = hex.bytes().iter().map(|b| Value::UInt((*b).into()));
+            Ok(Value::Seq(Seq::new(values.collect())))
+        };
+
         transcode_roundtrip::<Vec<sp_runtime::AccountId32>>(
             r#"[
                 5GrwvaEF5zXb26Fz9rcQpDWS57CtERHpNehXCPcNoHGKutQY,
@@ -621,13 +698,13 @@ mod tests {
                     Value::Tuple(
                         Tuple::new(
                             Some("AccountId32"),
-                            vec![Value::Bytes(Bytes::from_hex_string("0xd43593c715fdd31c61141abd04a99fd6822c8558854ccde39a5684e7a56da27d").unwrap())]
+                            vec![hex_to_bytes("0xd43593c715fdd31c61141abd04a99fd6822c8558854ccde39a5684e7a56da27d")?]
                         )
                     ),
                     Value::Tuple(
                         Tuple::new(
                             Some("AccountId32"),
-                            vec![Value::Bytes(Bytes::from_hex_string("0x8eaf04151687736326c9fea17e25fc5287613693c912909cb226aa4794f26a48").unwrap())]
+                            vec![hex_to_bytes("0x8eaf04151687736326c9fea17e25fc5287613693c912909cb226aa4794f26a48")?]
                         )
                     )
                 ]
@@ -678,4 +755,26 @@ mod tests {
             )),
         )
     }
+
+    #[test]
+    fn transcode_hex_literal_uints() -> Result<()> {
+        #[derive(scale::Encode, TypeInfo)]
+        struct S(u8, u16, u32, u64, u128);
+
+        transcode_roundtrip::<S>(
+            r#"S (0xDE, 0xDEAD, 0xDEADBEEF, 0xDEADBEEF12345678, 0xDEADBEEF0123456789ABCDEF01234567)"#,
+            Value::Tuple(Tuple::new(
+                Some("S"),
+                vec![
+                    Value::UInt(0xDE),
+                    Value::UInt(0xDEAD),
+                    Value::UInt(0xDEADBEEF),
+                    Value::UInt(0xDEADBEEF12345678),
+                    Value::UInt(0xDEADBEEF0123456789ABCDEF01234567),
+                ]
+                .into_iter()
+                .collect(),
+            )),
+        )
+    }
 }