diff --git a/src.ts/providers/base-provider.ts b/src.ts/providers/base-provider.ts
index b75ae8ff..824a9b57 100644
--- a/src.ts/providers/base-provider.ts
+++ b/src.ts/providers/base-provider.ts
@@ -247,6 +247,9 @@ function checkTransactionResponse(transaction: any): TransactionResponse {
     if (typeof(networkId) !== 'number') { networkId = 0; }
 
     result.networkId = networkId;
+    if (result.chainId == null && networkId != null) {
+        result.chainId = networkId;
+    }
 
     // 0x0000... should actually be null
     if (result.blockHash && result.blockHash.replace(/0/g, '') === 'x') {