diff --git a/src/adapters/_node/request.ts b/src/adapters/_node/request.ts
index e7a35a8..654e7f1 100644
--- a/src/adapters/_node/request.ts
+++ b/src/adapters/_node/request.ts
@@ -26,7 +26,11 @@ export const NodeRequest: {
 
     // @ts-expect-error
     static [Symbol.hasInstance](instance) {
-      return instance instanceof NativeRequest;
+      if (this === PatchedRequest) {
+        return instance instanceof NativeRequest;
+      } else {
+        return Object.prototype.isPrototypeOf.call(this.prototype, instance);
+      }
     }
 
     constructor(
diff --git a/test/_fixture.ts b/test/_fixture.ts
index beb19fd..e90dd07 100644
--- a/test/_fixture.ts
+++ b/test/_fixture.ts
@@ -102,7 +102,19 @@ export const fixture: (
           return new _Response(`ip: ${req.ip}`);
         }
         case "/req-instanceof": {
-          return new _Response(req instanceof Request ? "yes" : "no");
+          class MyRequst extends Request {}
+          return Response.json({
+            instanceofRequest: req instanceof Request ? "yes" : "no",
+            instanceofExtended: req instanceof MyRequst ? "yes" : "no",
+          });
+        }
+        case "/extended-req-instanceof": {
+          class MyRequst extends Request {}
+          const myReq = new MyRequst("http://example.com");
+          return Response.json({
+            instanceofRequest: myReq instanceof Request ? "yes" : "no",
+            instanceofExtended: myReq instanceof MyRequst ? "yes" : "no",
+          });
         }
         case "/req-headers-instanceof": {
           return new _Response(req.headers instanceof Headers ? "yes" : "no");
diff --git a/test/_tests.ts b/test/_tests.ts
index 5fb05a8..3329317 100644
--- a/test/_tests.ts
+++ b/test/_tests.ts
@@ -24,7 +24,19 @@ export function addTests(opts: {
   test("request instanceof Request", async () => {
     const response = await fetch(url("/req-instanceof"));
     expect(response.status).toBe(200);
-    expect(await response.text()).toMatch("yes");
+    expect(await response.json()).toMatchObject({
+      instanceofRequest: "yes",
+      instanceofExtended: "no",
+    });
+  });
+
+  test("extended request instanceof Request", async () => {
+    const response = await fetch(url("/extended-req-instanceof"));
+    expect(response.status).toBe(200);
+    expect(await response.json()).toMatchObject({
+      instanceofRequest: "yes",
+      instanceofExtended: "yes",
+    });
   });
 
   test("request.headers instanceof Headers", async () => {