diff --git a/packages/relay/src/formatters.ts b/packages/relay/src/formatters.ts
index b00ebddb93..870ff5b1e7 100644
--- a/packages/relay/src/formatters.ts
+++ b/packages/relay/src/formatters.ts
@@ -147,7 +147,6 @@ const formatContractResult = (cr: any) => {
   const commonFields = {
     blockHash: toHash32(cr.block_hash),
     blockNumber: nullableNumberTo0x(cr.block_number),
-    chainId: cr.chain_id,
     from: cr.from.substring(0, 42),
     gas: nanOrNumberTo0x(cr.gas_used),
     gasPrice: toNullIfEmptyHex(cr.gas_price),
@@ -161,6 +160,10 @@ const formatContractResult = (cr: any) => {
     type: nullableNumberTo0x(cr.type),
     v: cr.type === null ? null : nanOrNumberTo0x(cr.v),
     value: nanOrNumberTo0x(cr.amount),
+    // for legacy EIP155 with tx.chainId=0x0, mirror-node will return a '0x' (EMPTY_HEX) value for contract result's chain_id
+    //   which is incompatibile with certain tools (i.e. foundry). By setting this field, chainId, to undefined, the end jsonrpc
+    //   object will leave out this field, which is the proper behavior for other tools to be compatible with.
+    chainId: cr.chain_id === EMPTY_HEX ? undefined : cr.chain_id,
   };
 
   switch (cr.type) {
diff --git a/packages/relay/tests/lib/formatters.spec.ts b/packages/relay/tests/lib/formatters.spec.ts
index 78b190bf02..ef61d5c63a 100644
--- a/packages/relay/tests/lib/formatters.spec.ts
+++ b/packages/relay/tests/lib/formatters.spec.ts
@@ -252,6 +252,11 @@ describe('Formatters', () => {
       expect(formattedResult.yParity).to.equal('0x0');
       expect(formattedResult.value).to.equal('0x0');
     });
+
+    it('Should not include chainId field for legacy EIP155 transaction (tx.chainId=0x0)', () => {
+      const formattedResult: any = formatContractResult({ ...contractResult, chain_id: '0x' });
+      expect(formattedResult.chainId).to.be.undefined;
+    });
   });
 
   describe('prepend0x', () => {
diff --git a/packages/server/tests/acceptance/rpc_batch1.spec.ts b/packages/server/tests/acceptance/rpc_batch1.spec.ts
index 4d9733d0b2..68213ff190 100644
--- a/packages/server/tests/acceptance/rpc_batch1.spec.ts
+++ b/packages/server/tests/acceptance/rpc_batch1.spec.ts
@@ -957,6 +957,26 @@ describe('@api-batch-1 RPC Server Acceptance Tests', function () {
         expect(balanceChange.toString()).to.eq(Number(ONE_TINYBAR).toString());
       });
 
+      it('should return transaction result with no chainId field for legacy EIP155 transactions  (with no chainId i.e. chainId=0x0)', async function () {
+        const transaction = {
+          ...defaultLegacyTransactionData,
+          to: parentContractAddress,
+          nonce: await relay.getAccountNonce(accounts[1].address, requestId),
+          gasPrice: await relay.gasPrice(requestId),
+        };
+        const signedTx = await accounts[1].wallet.signTransaction(transaction);
+        const transactionHash = await relay.sendRawTransaction(signedTx, requestId);
+
+        const transactionResult = await relay.call(
+          RelayCalls.ETH_ENDPOINTS.ETH_GET_TRANSACTION_BY_HASH,
+          [transactionHash],
+          requestId,
+        );
+
+        const result = Object.prototype.hasOwnProperty.call(transactionResult, 'chainId');
+        expect(result).to.be.false;
+      });
+
       it('should fail "eth_sendRawTransaction" for Legacy transactions (with gas price too low)', async function () {
         const transaction = {
           ...defaultLegacyTransactionData,