diff --git a/CMakeLists.txt b/CMakeLists.txt
index ebe7c002..b810f14a 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -42,7 +42,7 @@ HunterGate(
 )
 
 project(eos_evm_node)
-set(PROJECT_VERSION 0.5.0)
+set(PROJECT_VERSION 0.5.1)
 
 string(REGEX MATCH "([0-9]+)\\.([0-9]+)\\.([0-9]+)" _ ${PROJECT_VERSION})
 set(PROJECT_VERSION_MAJOR ${CMAKE_MATCH_1})
diff --git a/contract/include/evm_runtime/evm_contract.hpp b/contract/include/evm_runtime/evm_contract.hpp
index e1893d8e..f6955fba 100644
--- a/contract/include/evm_runtime/evm_contract.hpp
+++ b/contract/include/evm_runtime/evm_contract.hpp
@@ -131,7 +131,7 @@ class [[eosio::contract]] evm_contract : public contract
       check((_config.get().status & static_cast<uint32_t>(status_flags::frozen)) == 0, "contract is frozen");
    }
 
-   silkworm::Receipt execute_tx(eosio::name miner, silkworm::Block& block, silkworm::Transaction& tx, silkworm::ExecutionProcessor& ep);
+   silkworm::Receipt execute_tx(eosio::name miner, silkworm::Block& block, silkworm::Transaction& tx, silkworm::ExecutionProcessor& ep, bool enforce_chain_id);
 
    uint64_t get_and_increment_nonce(const name owner);
 
diff --git a/contract/src/CMakeLists.txt b/contract/src/CMakeLists.txt
index a2574213..362b409d 100644
--- a/contract/src/CMakeLists.txt
+++ b/contract/src/CMakeLists.txt
@@ -20,7 +20,7 @@ if (WITH_LOGTIME)
 endif()
 
 add_compile_definitions(ANTELOPE)
-add_compile_definitions(PROJECT_VERSION="0.5.0")
+add_compile_definitions(PROJECT_VERSION="0.5.1")
 
 # ethash
 list(APPEND SOURCES 
diff --git a/contract/src/actions.cpp b/contract/src/actions.cpp
index 6dbafc09..f2cb43de 100644
--- a/contract/src/actions.cpp
+++ b/contract/src/actions.cpp
@@ -194,7 +194,7 @@ void check_result( ValidationResult r, const Transaction& txn, const char* desc
     eosio::check( false, std::move(err_msg));
 }
 
-Receipt evm_contract::execute_tx( eosio::name miner, Block& block, Transaction& tx, silkworm::ExecutionProcessor& ep ) {
+Receipt evm_contract::execute_tx( eosio::name miner, Block& block, Transaction& tx, silkworm::ExecutionProcessor& ep, bool enforce_chain_id) {
     //when being called as an inline action, clutch in allowance for reserved addresses & signatures by setting from_self=true
     const bool from_self = get_sender() == get_self();
 
@@ -244,6 +244,10 @@ Receipt evm_contract::execute_tx( eosio::name miner, Block& block, Transaction&
     else if(is_reserved_address(*tx.from))
         check(from_self, "bridge signature used outside of bridge transaction");
 
+    if(enforce_chain_id && !from_self) {
+        check(tx.chain_id.has_value(), "tx without chain-id");
+    }
+
     ValidationResult r = consensus::pre_validate_transaction(tx, ep.evm().block().header.number, ep.evm().config(),
                                                              ep.evm().block().header.base_fee_per_gas);
     check_result( r, tx, "pre_validate_transaction error" );
@@ -402,7 +406,7 @@ void evm_contract::pushtx( eosio::name miner, const bytes& rlptx ) {
     check(tx.max_priority_fee_per_gas == tx.max_fee_per_gas, "max_priority_fee_per_gas must be equal to max_fee_per_gas");
     check(tx.max_fee_per_gas >= current_config.gas_price, "gas price is too low");
 
-    auto receipt = execute_tx(miner, block, tx, ep);
+    auto receipt = execute_tx(miner, block, tx, ep, true);
 
     engine.finalize(ep.state(), ep.evm().block(), ep.evm().revision());
     ep.state().write_to_db(ep.evm().block().header.number);
@@ -570,7 +574,7 @@ bool evm_contract::gc(uint32_t max) {
         ByteView bv{(const uint8_t*)orlptx->data(), orlptx->size()};
         eosio::check(rlp::decode(bv,tx) == DecodingResult::kOk && bv.empty(), "unable to decode transaction");
 
-        execute_tx(eosio::name{}, block, tx, ep);
+        execute_tx(eosio::name{}, block, tx, ep, false);
     }
     engine.finalize(ep.state(), ep.evm().block(), ep.evm().revision());
     ep.state().write_to_db(ep.evm().block().header.number);
diff --git a/contract/tests/CMakeLists.txt b/contract/tests/CMakeLists.txt
index 65541ff0..ab15b757 100644
--- a/contract/tests/CMakeLists.txt
+++ b/contract/tests/CMakeLists.txt
@@ -33,6 +33,7 @@ add_eosio_test_executable( unit_test
     ${CMAKE_SOURCE_DIR}/gas_fee_tests.cpp
     ${CMAKE_SOURCE_DIR}/blockhash_tests.cpp
     ${CMAKE_SOURCE_DIR}/exec_tests.cpp
+    ${CMAKE_SOURCE_DIR}/chainid_tests.cpp
     ${CMAKE_SOURCE_DIR}/main.cpp
     ${CMAKE_SOURCE_DIR}/silkworm/core/silkworm/rlp/encode.cpp
     ${CMAKE_SOURCE_DIR}/silkworm/core/silkworm/rlp/decode.cpp
diff --git a/contract/tests/basic_evm_tester.cpp b/contract/tests/basic_evm_tester.cpp
index 7c028ef4..a9d7ece5 100644
--- a/contract/tests/basic_evm_tester.cpp
+++ b/contract/tests/basic_evm_tester.cpp
@@ -95,10 +95,15 @@ key256_t evm_eoa::address_key256() const
    return fixed_bytes<32>(buffer).get_array();
 }
 
-void evm_eoa::sign(silkworm::Transaction& trx)
+void evm_eoa::sign(silkworm::Transaction& trx) {
+   sign(trx, basic_evm_tester::evm_chain_id);
+}
+
+void evm_eoa::sign(silkworm::Transaction& trx, std::optional<uint64_t> evm_chain_id)
 {
    silkworm::Bytes rlp;
-   trx.chain_id = basic_evm_tester::evm_chain_id;
+   if(evm_chain_id.has_value())
+      trx.chain_id = evm_chain_id.value();
    trx.nonce = next_nonce++;
    silkworm::rlp::encode(rlp, trx, true, false);
    ethash::hash256 hash{silkworm::keccak256(rlp)};
diff --git a/contract/tests/basic_evm_tester.hpp b/contract/tests/basic_evm_tester.hpp
index a554faaa..56b79940 100644
--- a/contract/tests/basic_evm_tester.hpp
+++ b/contract/tests/basic_evm_tester.hpp
@@ -134,6 +134,7 @@ class evm_eoa
    key256_t address_key256() const;
 
    void sign(silkworm::Transaction& trx);
+   void sign(silkworm::Transaction& trx, std::optional<uint64_t> chain_id);
 
    ~evm_eoa();
 
diff --git a/contract/tests/chainid_tests.cpp b/contract/tests/chainid_tests.cpp
new file mode 100644
index 00000000..99e3ac89
--- /dev/null
+++ b/contract/tests/chainid_tests.cpp
@@ -0,0 +1,42 @@
+#include "basic_evm_tester.hpp"
+#include <silkworm/execution/address.hpp>
+
+using namespace evm_test;
+struct chain_id_tester : basic_evm_tester {
+   chain_id_tester() {
+      create_accounts({"alice"_n});
+      transfer_token(faucet_account_name, "alice"_n, make_asset(10000'0000));
+      init();
+   }
+};
+
+BOOST_AUTO_TEST_SUITE(chainid_evm_tests)
+BOOST_FIXTURE_TEST_CASE(chainid_tests, chain_id_tester) try {
+
+   // Bridge transactions are sent without chain id specified (must succeed)
+   evm_eoa evm1;
+   const int64_t to_bridge = 1000000; //100.000 EOS
+   transfer_token("alice"_n, "evm"_n, make_asset(to_bridge), evm1.address_0x());
+   auto balance_evm1 = evm_balance(evm1);
+   BOOST_REQUIRE(balance_evm1.has_value() && *balance_evm1 == 100_ether);
+
+   // Transactions without chain id specified must fail
+   evm_eoa evm2;
+   auto txn = generate_tx(evm2.address, 1_ether, 21000);
+   evm1.sign(txn, {});
+   BOOST_REQUIRE_EXCEPTION(pushtx(txn), eosio_assert_message_exception,
+    [](const eosio_assert_message_exception& e) {return testing::expect_assert_message(e, "assertion failure with message: tx without chain-id");});
+
+   // reuse nonce since previous signed transaction was rejected
+   evm1.next_nonce--;
+
+   // Transactions with chain id must succeed
+   evm_eoa evm3;
+   txn = generate_tx(evm3.address, 20_ether, 21000);
+   evm1.sign(txn, basic_evm_tester::evm_chain_id);
+   pushtx(txn);
+   auto balance_evm3 = evm_balance(evm3);
+   BOOST_REQUIRE(balance_evm3.has_value() && *balance_evm3 == 20_ether);
+
+} FC_LOG_AND_RETHROW()
+BOOST_AUTO_TEST_SUITE_END()