diff --git a/packages/api/src/SubmittableExtrinsic.ts b/packages/api/src/SubmittableExtrinsic.ts
index 7135abe06f..23cba72d4c 100644
--- a/packages/api/src/SubmittableExtrinsic.ts
+++ b/packages/api/src/SubmittableExtrinsic.ts
@@ -197,10 +197,10 @@ export default function createSubmittableExtrinsic<CodecResult, SubscriptionResu
                 } else {
                   assert(api.signer, 'no signer exists');
 
-                  updateId = await (api.signer as Signer).sign(_extrinsic, address, expandOptions({
-                    ...options,
-                    nonce
-                  }));
+                  updateId = await (api.signer as Signer).sign(_extrinsic, address, {
+                    ...expandOptions({ ...options, nonce }),
+                    genesisHash: api.genesisHash
+                  });
                 }
               }),
               switchMap(() => {
diff --git a/packages/api/src/types.ts b/packages/api/src/types.ts
index 613db4a5d2..3cad746c2d 100644
--- a/packages/api/src/types.ts
+++ b/packages/api/src/types.ts
@@ -189,11 +189,15 @@ export interface ApiBaseInterface<CodecResult, SubscriptionResult> extends Reado
   once: (type: ApiInterface$Events, handler: (...args: Array<any>) => any) => this;
 }
 
+export type SignerOptions = SignatureOptions & {
+  genesisHash: Hash
+};
+
 export interface Signer {
   /**
    * @description Signs an extrinsic, returning an id (>0) that can be used to retrieve updates
    */
-  sign (extrinsic: IExtrinsic, address: string, options: SignatureOptions): Promise<number>;
+  sign (extrinsic: IExtrinsic, address: string, options: SignerOptions): Promise<number>;
 
   /**
    * @description Receives an update for the extrinsic signed by a `signer.sign`