diff --git a/evm/src/cpu/kernel/interpreter.rs b/evm/src/cpu/kernel/interpreter.rs
index 81ce287b..1839aaf2 100644
--- a/evm/src/cpu/kernel/interpreter.rs
+++ b/evm/src/cpu/kernel/interpreter.rs
@@ -1,4 +1,5 @@
-use ethereum_types::{U256, U512};
+use ethereum_types::{BigEndianHash, U256, U512};
+use keccak_hash::keccak;
 
 /// Halt interpreter execution whenever a jump to this offset is done.
 const HALT_OFFSET: usize = 0xdeadbeef;
@@ -25,6 +26,11 @@ impl EvmMemory {
         U256::from_big_endian(&self.memory[offset..offset + 32])
     }
 
+    fn mload8(&mut self, offset: usize) -> u8 {
+        self.expand(offset + 1);
+        self.memory[offset]
+    }
+
     fn mstore(&mut self, offset: usize, value: U256) {
         self.expand(offset + 32);
         let value_be = {
@@ -119,7 +125,7 @@ impl<'a> Interpreter<'a> {
             0x1b => todo!(),                                           // "SHL",
             0x1c => todo!(),                                           // "SHR",
             0x1d => todo!(),                                           // "SAR",
-            0x20 => todo!(),                                           // "KECCAK256",
+            0x20 => self.run_sha3(),                                   // "SHA3",
             0x30 => todo!(),                                           // "ADDRESS",
             0x31 => todo!(),                                           // "BALANCE",
             0x32 => todo!(),                                           // "ORIGIN",
@@ -286,6 +292,16 @@ impl<'a> Interpreter<'a> {
         self.push(!x);
     }
 
+    fn run_sha3(&mut self) {
+        let offset = self.pop().as_usize();
+        let size = self.pop().as_usize();
+        let bytes = (offset..offset + size)
+            .map(|i| self.memory.mload8(i))
+            .collect::<Vec<_>>();
+        let hash = keccak(bytes);
+        self.push(hash.into_uint());
+    }
+
     fn run_pop(&mut self) {
         self.pop();
     }