diff --git a/packages/transactions/src.ts/index.ts b/packages/transactions/src.ts/index.ts
index 80c64ea4d1..111cc0c220 100644
--- a/packages/transactions/src.ts/index.ts
+++ b/packages/transactions/src.ts/index.ts
@@ -59,7 +59,7 @@ export interface Transaction {
     nonce: number;
 
     gasLimit: BigNumber;
-    gasPrice: BigNumber;
+    gasPrice?: BigNumber;
 
     data: string;
     value: BigNumber;