diff --git a/nimbus/evm/interpreter/gas_costs.nim b/nimbus/evm/interpreter/gas_costs.nim
index a145c49160..d6a1749681 100644
--- a/nimbus/evm/interpreter/gas_costs.nim
+++ b/nimbus/evm/interpreter/gas_costs.nim
@@ -630,6 +630,9 @@ template gasCosts(fork: EVMFork, prefix, ResultGasCostsName: untyped) =
           # 5c & 5d: Transient storage operations
           Tload:          fixed GasWarmStorageRead,
           Tstore:         fixed GasWarmStorageRead,
+          
+          # 5e: Memory copy
+          Mcopy:          memExpansion `prefix gasCopy`,
 
           # 5f, 60s & 70s: Push Operations
           Push0:          fixed GasBase,
diff --git a/nimbus/evm/interpreter/op_codes.nim b/nimbus/evm/interpreter/op_codes.nim
index c11f4890a1..46ec4f8bd5 100644
--- a/nimbus/evm/interpreter/op_codes.nim
+++ b/nimbus/evm/interpreter/op_codes.nim
@@ -130,7 +130,7 @@ type
     Tload =          0x5c, ## Load word from transient storage.
     Tstore =         0x5d, ## Save word to transient storage.
 
-    Nop0x5E =        0x5e, ## Transfers control to a subroutine.
+    Mcopy =          0x5e, ## Memory copy
 
     # 5f, 60s & 70s: Push Operations.
     Push0 =          0x5f, ## Place 0 on stack. EIP-3855
diff --git a/nimbus/evm/interpreter/op_handlers/oph_memory.nim b/nimbus/evm/interpreter/op_handlers/oph_memory.nim
index d3d0d06658..40c058bb51 100644
--- a/nimbus/evm/interpreter/op_handlers/oph_memory.nim
+++ b/nimbus/evm/interpreter/op_handlers/oph_memory.nim
@@ -321,6 +321,19 @@ const
       val  = k.cpt.stack.popInt()
     k.cpt.setTransientStorage(slot, val)
 
+  mCopyOp: Vm2OpFn = proc (k: var Vm2Ctx) =
+    ## 0x5e, Copy memory
+    let (dst, src, size) = k.cpt.stack.popInt(3)
+
+    let (dstPos, srcPos, len) =
+      (dst.cleanMemRef, src.cleanMemRef, size.cleanMemRef)
+
+    k.cpt.gasMeter.consumeGas(
+      k.cpt.gasCosts[Mcopy].m_handler(k.cpt.memory.len, max(dstPos, srcPos), len),
+      reason = "Mcopy fee")
+
+    k.cpt.memory.copy(dstPos, srcPos, len)
+
 #[
   EIP-2315: temporary disabled
   Reason  : not included in berlin hard fork
@@ -525,6 +538,14 @@ const
      info: "Save word to transient storage",
      exec: (prep: vm2OpIgnore,
             run:  tstoreOp,
+            post: vm2OpIgnore)),
+
+    (opCode: Mcopy,     ## 0x5e, Copy memory
+     forks: Vm2OpCancunAndLater,
+     name: "MCopy",
+     info: "Copy memory",
+     exec: (prep: vm2OpIgnore,
+            run:  mCopyOp,
             post: vm2OpIgnore))]
 
 #[
diff --git a/nimbus/evm/memory.nim b/nimbus/evm/memory.nim
index bbe0100746..f1271d2453 100644
--- a/nimbus/evm/memory.nim
+++ b/nimbus/evm/memory.nim
@@ -52,3 +52,15 @@ proc write*(memory: var Memory, startPos: Natural, value: openArray[byte]) =
   validateLte(startPos + size, memory.len)
   for z, b in value:
     memory.bytes[z + startPos] = b
+
+proc copy*(memory: var Memory, dst, src, len: Natural) =
+  if len <= 0: return
+  memory.extend(max(dst, src), len)
+  if dst == src:
+    return
+  elif dst < src:
+    for i in 0..<len:
+      memory.bytes[dst+i] = memory.bytes[src+i]
+  else: # src > dst
+    for i in countdown(len-1, 0):
+      memory.bytes[dst+i] = memory.bytes[src+i]
diff --git a/tests/test_op_memory.nim b/tests/test_op_memory.nim
index 14227ed501..060192bbcc 100644
--- a/tests/test_op_memory.nim
+++ b/tests/test_op_memory.nim
@@ -812,5 +812,113 @@ proc opMemoryMain*() =
         "0x00"
         "0x0000000000000000000000000000002000000000000000000000000000000000"
 
+    assembler:
+      title: "MCOPY 1"
+      code:
+        PUSH32 "0x0000000000000000000000000000000000000000000000000000000000000000"
+        PUSH1  "0x00"
+        MSTORE
+        PUSH32 "0x000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f"
+        PUSH1  "0x20"
+        MSTORE
+        PUSH1  "0x20" # len
+        PUSH1  "0x20" # src
+        PUSH1  "0x00" # dst
+        MCOPY
+      memory:
+        "0x000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f"
+        "0x000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f"
+      fork: Cancun
+
+    assembler:
+      title: "MCOPY 2: Overlap"
+      code:
+        PUSH32 "0x0101010101010101010101010101010101010101010101010101010101010101"
+        PUSH1  "0x00"
+        MSTORE
+        PUSH1  "0x20" # len
+        PUSH1  "0x00" # src
+        PUSH1  "0x00" # dst
+        MCOPY
+      memory:
+        "0x0101010101010101010101010101010101010101010101010101010101010101"
+      fork: Cancun
+
+    assembler:
+      title: "MCOPY 3"
+      code:
+        PUSH1 "0x00"
+        PUSH1 "0x00"
+        MSTORE8
+        PUSH1 "0x01"
+        PUSH1 "0x01"
+        MSTORE8
+        PUSH1 "0x02"
+        PUSH1 "0x02"
+        MSTORE8
+        PUSH1 "0x03"
+        PUSH1 "0x03"
+        MSTORE8
+        PUSH1 "0x04"
+        PUSH1 "0x04"
+        MSTORE8
+        PUSH1 "0x05"
+        PUSH1 "0x05"
+        MSTORE8
+        PUSH1 "0x06"
+        PUSH1 "0x06"
+        MSTORE8
+        PUSH1 "0x07"
+        PUSH1 "0x07"
+        MSTORE8
+        PUSH1 "0x08"
+        PUSH1 "0x08"
+        MSTORE8
+        PUSH1  "0x08" # len
+        PUSH1  "0x01" # src
+        PUSH1  "0x00" # dst
+        MCOPY
+      memory:
+        "0x0102030405060708080000000000000000000000000000000000000000000000"
+      fork: Cancun
+
+    assembler:
+      title: "MCOPY 4"
+      code:
+        PUSH1 "0x00"
+        PUSH1 "0x00"
+        MSTORE8
+        PUSH1 "0x01"
+        PUSH1 "0x01"
+        MSTORE8
+        PUSH1 "0x02"
+        PUSH1 "0x02"
+        MSTORE8
+        PUSH1 "0x03"
+        PUSH1 "0x03"
+        MSTORE8
+        PUSH1 "0x04"
+        PUSH1 "0x04"
+        MSTORE8
+        PUSH1 "0x05"
+        PUSH1 "0x05"
+        MSTORE8
+        PUSH1 "0x06"
+        PUSH1 "0x06"
+        MSTORE8
+        PUSH1 "0x07"
+        PUSH1 "0x07"
+        MSTORE8
+        PUSH1 "0x08"
+        PUSH1 "0x08"
+        MSTORE8
+        PUSH1  "0x08" # len
+        PUSH1  "0x00" # src
+        PUSH1  "0x01" # dst
+        MCOPY
+      memory:
+        "0x0000010203040506070000000000000000000000000000000000000000000000"
+      fork: Cancun
+
 when isMainModule:
   opMemoryMain()