diff --git a/async/delay.ts b/async/delay.ts
index 990e13d73..57606f6d6 100644
--- a/async/delay.ts
+++ b/async/delay.ts
@@ -38,13 +38,11 @@ export interface DelayOptions {
  */
 export function delay(ms: number, options: DelayOptions = {}): Promise<void> {
   const { signal, persistent } = options;
-  if (signal?.aborted) {
-    return Promise.reject(new DOMException("Delay was aborted.", "AbortError"));
-  }
+  if (signal?.aborted) return Promise.reject(signal.reason);
   return new Promise((resolve, reject) => {
     const abort = () => {
       clearTimeout(i);
-      reject(new DOMException("Delay was aborted.", "AbortError"));
+      reject(signal?.reason);
     };
     const done = () => {
       signal?.removeEventListener("abort", abort);
diff --git a/async/delay_test.ts b/async/delay_test.ts
index 6bb138a5b..bae5c4e84 100644
--- a/async/delay_test.ts
+++ b/async/delay_test.ts
@@ -1,6 +1,17 @@
 // Copyright 2018-2023 the Deno authors. All rights reserved. MIT license.
 import { delay } from "./delay.ts";
-import { assert, assertRejects } from "../assert/mod.ts";
+import {
+  assert,
+  assertInstanceOf,
+  assertRejects,
+  assertStrictEquals,
+} from "../assert/mod.ts";
+
+// https://dom.spec.whatwg.org/#interface-AbortSignal
+function assertIsDefaultAbortReason(reason: unknown) {
+  assertInstanceOf(reason, DOMException);
+  assertStrictEquals(reason.name, "AbortError");
+}
 
 Deno.test("[async] delay", async function () {
   const start = new Date();
@@ -17,14 +28,45 @@ Deno.test("[async] delay with abort", async function () {
   const { signal } = abort;
   const delayedPromise = delay(100, { signal });
   setTimeout(() => abort.abort(), 0);
-  await assertRejects(
-    () => delayedPromise,
-    DOMException,
-    "Delay was aborted",
-  );
-
+  const cause = await assertRejects(() => delayedPromise);
   const diff = new Date().getTime() - start.getTime();
   assert(diff < 100);
+  assertIsDefaultAbortReason(cause);
+});
+
+Deno.test("[async] delay with abort reason", async function (ctx) {
+  async function assertRejectsReason(reason: unknown) {
+    const start = new Date();
+    const abort = new AbortController();
+    const { signal } = abort;
+    const delayedPromise = delay(100, { signal });
+    setTimeout(() => abort.abort(reason), 0);
+    const cause = await assertRejects(() => delayedPromise);
+    const diff = new Date().getTime() - start.getTime();
+    assert(diff < 100);
+    assertStrictEquals(cause, reason);
+  }
+
+  await ctx.step("not-undefined values", async () => {
+    await Promise.all([
+      null,
+      new Error("Timeout cancelled"),
+      new DOMException("Timeout cancelled", "AbortError"),
+      new DOMException("The signal has been aborted", "AbortError"),
+    ].map(assertRejectsReason));
+  });
+
+  await ctx.step("undefined", async () => {
+    const start = new Date();
+    const abort = new AbortController();
+    const { signal } = abort;
+    const delayedPromise = delay(100, { signal });
+    setTimeout(() => abort.abort(), 0);
+    const cause = await assertRejects(() => delayedPromise);
+    const diff = new Date().getTime() - start.getTime();
+    assert(diff < 100);
+    assertIsDefaultAbortReason(cause);
+  });
 });
 
 Deno.test("[async] delay with non-aborted signal", async function () {
@@ -32,7 +74,6 @@ Deno.test("[async] delay with non-aborted signal", async function () {
   const abort = new AbortController();
   const { signal } = abort;
   const delayedPromise = delay(100, { signal });
-  // abort.abort()
   const result = await delayedPromise;
   const diff = new Date().getTime() - start.getTime();
   assert(result === undefined);
@@ -57,12 +98,8 @@ Deno.test("[async] delay with already aborted signal", async function () {
   abort.abort();
   const { signal } = abort;
   const delayedPromise = delay(100, { signal });
-  await assertRejects(
-    () => delayedPromise,
-    DOMException,
-    "Delay was aborted",
-  );
-
+  const cause = await assertRejects(() => delayedPromise);
   const diff = new Date().getTime() - start.getTime();
   assert(diff < 100);
+  assertIsDefaultAbortReason(cause);
 });