diff --git a/Cargo.lock b/Cargo.lock
index 0c20d3890a37ffd8ce2e3cb5d42a02864816245e..49d4321a723ec5e7b425e92d879c1ce4ff2607d2 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -269,6 +269,7 @@ dependencies = [
  "assert_matches 1.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "async-std 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "cargo_metadata 0.9.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "colored 1.9.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "env_logger 0.7.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "futures 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "heck 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -284,6 +285,7 @@ dependencies = [
  "url 1.7.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "wabt 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "walkdir 2.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "which 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "zip 0.5.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -346,6 +348,16 @@ dependencies = [
  "cc 1.0.50 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "colored"
+version = "1.9.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "atty 0.2.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "const-random"
 version = "0.1.8"
@@ -2952,6 +2964,15 @@ dependencies = [
  "nom 4.2.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "which"
+version = "3.1.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "failure 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.66 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "winapi"
 version = "0.2.8"
@@ -3074,6 +3095,7 @@ dependencies = [
 "checksum clear_on_drop 0.2.3 (registry+https://github.com/rust-lang/crates.io-index)" = "97276801e127ffb46b66ce23f35cc96bd454fa311294bced4bbace7baa8b1d17"
 "checksum cloudabi 0.0.3 (registry+https://github.com/rust-lang/crates.io-index)" = "ddfc5b9aa5d4507acaf872de71051dfd0e309860e88966e1051e462a077aac4f"
 "checksum cmake 0.1.42 (registry+https://github.com/rust-lang/crates.io-index)" = "81fb25b677f8bf1eb325017cb6bb8452f87969db0fedb4f757b297bee78a7c62"
+"checksum colored 1.9.2 (registry+https://github.com/rust-lang/crates.io-index)" = "8815e2ab78f3a59928fc32e141fbeece88320a240e43f47b2fd64ea3a88a5b3d"
 "checksum const-random 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "2f1af9ac737b2dd2d577701e59fd09ba34822f6f2ebdb30a7647405d9e55e16a"
 "checksum const-random-macro 0.1.8 (registry+https://github.com/rust-lang/crates.io-index)" = "25e4c606eb459dd29f7c57b2e0879f2b6f14ee130918c2b78ccb58a9624e6c7a"
 "checksum constant_time_eq 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)" = "245097e9a4535ee1e3e3931fcfcd55a796a44c643e8596ff6566d68f09b87bbc"
@@ -3350,6 +3372,7 @@ dependencies = [
 "checksum webpki 0.21.0 (registry+https://github.com/rust-lang/crates.io-index)" = "d7e664e770ac0110e2384769bcc59ed19e329d81f555916a6e072714957b81b4"
 "checksum webpki-roots 0.17.0 (registry+https://github.com/rust-lang/crates.io-index)" = "a262ae37dd9d60f60dd473d1158f9fbebf110ba7b6a5051c8160460f6043718b"
 "checksum weedle 0.10.0 (registry+https://github.com/rust-lang/crates.io-index)" = "3bb43f70885151e629e2a19ce9e50bd730fd436cfd4b666894c9ce4de9141164"
+"checksum which 3.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "5475d47078209a02e60614f7ba5e645ef3ed60f771920ac1906d7c1cc65024c8"
 "checksum winapi 0.2.8 (registry+https://github.com/rust-lang/crates.io-index)" = "167dc9d6949a9b857f3451275e911c3f44255842c1f7a76f33c55103a909087a"
 "checksum winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)" = "8093091eeb260906a183e6ae1abdba2ef5ef2257a21801128899c3fc699229c6"
 "checksum winapi-build 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)" = "2d315eee3b34aca4797b2da6b13ed88266e6d612562a0c46390af8299fc699bc"
diff --git a/Cargo.toml b/Cargo.toml
index 3cee7d4349b3b0abdb420b560bb4992dd6ea6e75..b858e4be8582e859fba35d37e6c97cf7b1ed29cd 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -25,6 +25,8 @@ pwasm-utils = "0.12"
 parity-wasm = "0.41"
 cargo_metadata = "0.9"
 codec = { package = "parity-scale-codec", version = "1.1" }
+which = "3.1.0"
+colored = "1.9"
 
 # dependencies for optional extrinsics feature
 async-std = { version = "1.2.0", optional = true }
diff --git a/src/cmd/build.rs b/src/cmd/build.rs
index b7deddfb73bf4d1108f60579e8cb7557e6a59bcd..c054f591ccb9040882a2d3e56aa0c25bc61e404a 100644
--- a/src/cmd/build.rs
+++ b/src/cmd/build.rs
@@ -14,10 +14,16 @@
 // You should have received a copy of the GNU General Public License
 // along with ink!.  If not, see <http://www.gnu.org/licenses/>.
 
-use std::path::PathBuf;
+use std::{
+    fs::metadata,
+    io::{self, Write},
+    path::PathBuf,
+    process::Command,
+};
 
 use anyhow::{Context, Result};
 use cargo_metadata::MetadataCommand;
+use colored::Colorize;
 use parity_wasm::elements::{External, MemoryType, Module, Section};
 
 /// This is the maximum number of pages available for a contract to allocate.
@@ -25,6 +31,7 @@ const MAX_MEMORY_PAGES: u32 = 16;
 
 /// Relevant metadata obtained from Cargo.toml.
 pub struct CrateMetadata {
+    package_name: String,
     original_wasm: PathBuf,
     pub dest_wasm: PathBuf,
 }
@@ -62,10 +69,11 @@ pub fn collect_crate_metadata(working_dir: Option<&PathBuf>) -> Result<CrateMeta
 
     // {target_dir}/{package_name}.wasm
     let mut dest_wasm = metadata.target_directory.clone();
-    dest_wasm.push(package_name);
+    dest_wasm.push(package_name.clone());
     dest_wasm.set_extension("wasm");
 
     Ok(CrateMetadata {
+        package_name,
         original_wasm,
         dest_wasm,
     })
@@ -153,20 +161,87 @@ fn post_process_wasm(crate_metadata: &CrateMetadata) -> Result<()> {
     Ok(())
 }
 
+/// Attempts to perform optional wasm optimization using `wasm-opt`.
+///
+/// The intention is to reduce the size of bloated wasm binaries as a result of missing
+/// optimizations (or bugs?) between Rust and Wasm.
+///
+/// This step depends on the `wasm-opt` tool being installed. If it is not the build will still
+/// succeed, and the user will be encouraged to install it for further optimizations.
+fn optimize_wasm(crate_metadata: &CrateMetadata) -> Result<()> {
+    // check `wasm-opt` installed
+    if which::which("wasm-opt").is_err() {
+        println!(
+            "{}",
+            "wasm-opt is not installed. Install this tool on your system in order to \n\
+             reduce the size of your contract's Wasm binary. \n\
+             See https://github.com/WebAssembly/binaryen#tools"
+                .bright_yellow()
+        );
+        return Ok(());
+    }
+
+    let mut optimized = crate_metadata.dest_wasm.clone();
+    optimized.set_file_name(format!("{}-opt.wasm", crate_metadata.package_name));
+
+    let output = Command::new("wasm-opt")
+        .arg(crate_metadata.dest_wasm.as_os_str())
+        .arg("-O3") // execute -O3 optimization passes (spends potentially a lot of time optimizing)
+        .arg("-o")
+        .arg(optimized.as_os_str())
+        .output()?;
+
+    if !output.status.success() {
+        // Dump the output streams produced by wasm-opt into the stdout/stderr.
+        io::stdout().write_all(&output.stdout)?;
+        io::stderr().write_all(&output.stderr)?;
+        anyhow::bail!("wasm-opt optimization failed");
+    }
+
+    let original_size = metadata(&crate_metadata.dest_wasm)?.len() / 1000;
+    let optimized_size = metadata(&optimized)?.len() / 1000;
+    println!(
+        " Original wasm size: {}K, Optimized: {}K",
+        original_size, optimized_size
+    );
+
+    // overwrite existing destination wasm file with the optimised version
+    std::fs::rename(&optimized, &crate_metadata.dest_wasm)?;
+    Ok(())
+}
+
 /// Executes build of the smart-contract which produces a wasm binary that is ready for deploying.
 ///
 /// It does so by invoking build by cargo and then post processing the final binary.
 pub(crate) fn execute_build(working_dir: Option<&PathBuf>) -> Result<String> {
-    println!(" [1/3] Collecting crate metadata");
+    println!(
+        " {} {}",
+        "[1/4]".bold(),
+        "Collecting crate metadata".bright_green().bold()
+    );
     let crate_metadata = collect_crate_metadata(working_dir)?;
-    println!(" [2/3] Building cargo project");
+    println!(
+        " {} {}",
+        "[2/4]".bold(),
+        "Building cargo project".bright_green().bold()
+    );
     build_cargo_project(working_dir)?;
-    println!(" [3/3] Post processing wasm file");
+    println!(
+        " {} {}",
+        "[3/4]".bold(),
+        "Post processing wasm file".bright_green().bold()
+    );
     post_process_wasm(&crate_metadata)?;
+    println!(
+        " {} {}",
+        "[4/4]".bold(),
+        "Optimizing wasm file".bright_green().bold()
+    );
+    optimize_wasm(&crate_metadata)?;
 
     Ok(format!(
-        "Your contract is ready.\nYou can find it here:\n{}",
-        crate_metadata.dest_wasm.display()
+        "\nYour contract is ready. You can find it here:\n{}",
+        crate_metadata.dest_wasm.display().to_string().bold()
     ))
 }