diff --git a/examples/capi.c b/examples/capi.c
index 3d098931..785532cf 100644
--- a/examples/capi.c
+++ b/examples/capi.c
@@ -66,6 +66,14 @@ static void get_balance(struct evm_uint256be* result,
     *result = balance(context, address);
 }
 
+static size_t get_code_size(struct evm_context* context, const struct evm_address* address)
+{
+    printf("EVM-C: CODESIZE @");
+    print_address(address);
+    printf("\n");
+    return 0;
+}
+
 static size_t get_code(const uint8_t** code,
                        struct evm_context* context,
                        const struct evm_address* address)
@@ -121,6 +129,7 @@ static const struct evm_context_fn_table ctx_fn_table = {
     get_storage,
     set_storage,
     get_balance,
+    get_code_size,
     get_code,
     selfdestruct,
     call,
diff --git a/include/evm.h b/include/evm.h
index 32f633fe..786f2bf4 100644
--- a/include/evm.h
+++ b/include/evm.h
@@ -336,14 +336,21 @@ typedef void (*evm_get_balance_fn)(struct evm_uint256be* result,
                                    struct evm_context* context,
                                    const struct evm_address* address);
 
+/// Get code size callback function.
+///
+/// This callback function is used by an EVM to get the size of the code stored
+/// in the account at the given address. For accounts not having a code, this
+/// function returns 0.
+typedef size_t (*evm_get_code_size_fn)(struct evm_context* context,
+                                       const struct evm_address* address);
+
 /// Get code callback function.
 ///
 /// This callback function is used by an EVM to get the code of a contract of
 /// given address.
 ///
-/// @param[out] result_code  The pointer to the contract code. This argument is
-///                          optional. If NULL is provided, the host MUST only
-///                          return the code size. It will be freed by the Client.
+/// @param[out] result_code  The pointer to the contract code.
+///                          It will be freed by the Client.
 /// @param      context      The pointer to the Host execution context.
 ///                          @see ::evm_context.
 /// @param      address      The address of the contract.
@@ -408,6 +415,7 @@ struct evm_context_fn_table {
     evm_get_storage_fn get_storage;
     evm_set_storage_fn set_storage;
     evm_get_balance_fn get_balance;
+    evm_get_code_size_fn get_code_size;
     evm_get_code_fn get_code;
     evm_selfdestruct_fn selfdestruct;
     evm_call_fn call;
diff --git a/libevmjit/Ext.cpp b/libevmjit/Ext.cpp
index c47dcb6d..2ca59629 100644
--- a/libevmjit/Ext.cpp
+++ b/libevmjit/Ext.cpp
@@ -136,6 +136,23 @@ llvm::Function* getGetBalanceFunc(llvm::Module* _module)
 	return func;
 }
 
+llvm::Function* getGetCodeSizeFunc(llvm::Module* _module)
+{
+	static const auto funcName = "evm.codesize";
+	auto func = _module->getFunction(funcName);
+	if (!func)
+	{
+		auto addrTy = llvm::IntegerType::get(_module->getContext(), 160);
+		auto fty = llvm::FunctionType::get(
+			Type::Size, {Type::EnvPtr, addrTy->getPointerTo()}, false);
+		func = llvm::Function::Create(fty, llvm::Function::ExternalLinkage, funcName, _module);
+		func->addAttribute(2, llvm::Attribute::ReadOnly);
+		func->addAttribute(2, llvm::Attribute::NoAlias);
+		func->addAttribute(2, llvm::Attribute::NoCapture);
+	}
+	return func;
+}
+
 llvm::Function* getGetCodeFunc(llvm::Module* _module)
 {
 	static const auto funcName = "evm.code";
@@ -482,13 +499,12 @@ MemoryRef Ext::extcode(llvm::Value* _address)
 
 llvm::Value* Ext::extcodesize(llvm::Value* _address)
 {
-	auto func = getGetCodeFunc(getModule());
+	auto func = getGetCodeSizeFunc(getModule());
 	auto addrTy = m_builder.getIntNTy(160);
 	auto address = Endianness::toBE(m_builder, m_builder.CreateTrunc(_address, addrTy));
 	auto pAddr = m_builder.CreateBitCast(getArgAlloca(), addrTy->getPointerTo());
 	m_builder.CreateStore(address, pAddr);
-	auto ignoreCode = llvm::ConstantPointerNull::get(Type::BytePtr->getPointerTo());
-	auto size = createCABICall(func, {ignoreCode, getRuntimeManager().getEnvPtr(), pAddr});
+	auto size = createCABICall(func, {getRuntimeManager().getEnvPtr(), pAddr});
 	return m_builder.CreateZExt(size, Type::Word);
 }
 
diff --git a/libevmjit/JIT.cpp b/libevmjit/JIT.cpp
index 70f4bd39..96c67678 100644
--- a/libevmjit/JIT.cpp
+++ b/libevmjit/JIT.cpp
@@ -249,6 +249,7 @@ class SymbolResolver : public llvm::SectionMemoryManager
 			.Case("evm.sload", reinterpret_cast<uint64_t>(jit.host->get_storage))
 			.Case("evm.sstore", reinterpret_cast<uint64_t>(jit.host->set_storage))
 			.Case("evm.balance", reinterpret_cast<uint64_t>(jit.host->get_balance))
+			.Case("evm.codesize", reinterpret_cast<uint64_t>(jit.host->get_code_size))
 			.Case("evm.code", reinterpret_cast<uint64_t>(jit.host->get_code))
 			.Case("evm.selfdestruct", reinterpret_cast<uint64_t>(jit.host->selfdestruct))
 			.Case("evm.call", reinterpret_cast<uint64_t>(call_v2))