diff --git a/types/node/index.d.ts b/types/node/index.d.ts
index 7ad7ca3049..c1974ef350 100644
--- a/types/node/index.d.ts
+++ b/types/node/index.d.ts
@@ -6415,7 +6415,7 @@ declare module "stream" {
 
         export class PassThrough extends Transform { }
 
-        export function finished(stream: NodeJS.ReadableStream | NodeJS.WritableStream | NodeJS.ReadWriteStream, callback?: (err: NodeJS.ErrnoException) => void): () => void;
+        export function finished(stream: NodeJS.ReadableStream | NodeJS.WritableStream | NodeJS.ReadWriteStream, callback: (err?: NodeJS.ErrnoException) => void): () => void;
         export namespace finished {
             export function __promisify__(stream: NodeJS.ReadableStream | NodeJS.WritableStream | NodeJS.ReadWriteStream): Promise<void>;
         }
diff --git a/types/node/node-tests.ts b/types/node/node-tests.ts
index 731db242e8..3feb7a4a86 100644
--- a/types/node/node-tests.ts
+++ b/types/node/node-tests.ts
@@ -1124,10 +1124,10 @@ function simplified_stream_ctor_test() {
 }
 
 function streamPipelineFinished() {
-    const cancel = stream.finished(process.stdin, (err: Error) => {});
+    const cancel = stream.finished(process.stdin, (err?: Error) => {});
     cancel();
 
-    stream.pipeline(process.stdin, process.stdout, (err: Error) => {});
+    stream.pipeline(process.stdin, process.stdout, (err?: Error) => {});
 }
 
 async function asyncStreamPipelineFinished() {