diff --git a/src/types/guards.ts b/src/types/guards.ts
index 1275ce0..9409586 100644
--- a/src/types/guards.ts
+++ b/src/types/guards.ts
@@ -1,6 +1,7 @@
 import {
   Hex,
   isAddress,
+  isHex,
   parseTransaction,
   serializeTransaction,
   TransactionSerializable,
@@ -30,7 +31,11 @@ const isTypedDataDomain = (domain: unknown): domain is TypedDataDomain => {
   return Object.entries(candidate).every(([key, value]) => {
     switch (key) {
       case "chainId":
-        return typeof value === "undefined" || typeof value === "number";
+        return (
+          typeof value === "undefined" ||
+          typeof value === "number" ||
+          isHex(value)
+        );
       case "name":
       case "version":
         return typeof value === "undefined" || typeof value === "string";
diff --git a/tests/unit/types.guards.test.ts b/tests/unit/types.guards.test.ts
index e123621..af73c31 100644
--- a/tests/unit/types.guards.test.ts
+++ b/tests/unit/types.guards.test.ts
@@ -89,6 +89,48 @@ describe("isEIP712TypedData", () => {
       expect(isEIP712TypedData(item)).toBe(false)
     );
   });
+
+  it("recognizes safe EIP712 Typed data (with hex chainId)", async () => {
+    const safeTypedData = {
+      types: {
+        SafeTx: [
+          { name: "to", type: "address" },
+          { name: "value", type: "uint256" },
+          { name: "data", type: "bytes" },
+          { name: "operation", type: "uint8" },
+          { name: "safeTxGas", type: "uint256" },
+          { name: "baseGas", type: "uint256" },
+          { name: "gasPrice", type: "uint256" },
+          { name: "gasToken", type: "address" },
+          { name: "refundReceiver", type: "address" },
+          { name: "nonce", type: "uint256" },
+        ],
+        EIP712Domain: [
+          { name: "chainId", type: "uint256" },
+          { name: "verifyingContract", type: "address" },
+        ],
+      },
+      domain: {
+        chainId: "0xaa36a7",
+        verifyingContract: "0x7fa8e8264985c7525fc50f98ac1a9b3765405489",
+      },
+      primaryType: "SafeTx",
+      message: {
+        to: "0x102543f7e6b5786a444cc89ff73012825d13000d",
+        value: "100000000000000000",
+        data: "0x",
+        operation: "0",
+        safeTxGas: "0",
+        baseGas: "0",
+        gasPrice: "0",
+        gasToken: "0x0000000000000000000000000000000000000000",
+        refundReceiver: "0x0000000000000000000000000000000000000000",
+        nonce: "0",
+      },
+    };
+
+    expect(isEIP712TypedData(safeTypedData)).toBe(true);
+  });
 });
 
 describe("isTransactionSerializable", () => {