diff --git a/src/listener.ts b/src/listener.ts
index 2f266d6..8e92635 100644
--- a/src/listener.ts
+++ b/src/listener.ts
@@ -224,7 +224,7 @@ export const getRequestListener = (
     }
 
     try {
-      return responseViaResponseObject(res, outgoing, options)
+      return await responseViaResponseObject(res, outgoing, options)
     } catch (e) {
       return handleResponseError(e, outgoing)
     }
diff --git a/test/listener.test.ts b/test/listener.test.ts
index 1f20892..bbb8316 100644
--- a/test/listener.test.ts
+++ b/test/listener.test.ts
@@ -64,6 +64,21 @@ describe('Invalid request', () => {
       expect(res.status).toBe(400)
     })
   })
+
+  describe('malformed body response', () => {
+    const malformedResponse = {
+      body: 'content',
+    }
+    const requestListener = getRequestListener(() => malformedResponse, {
+      hostname: 'example.com',
+    })
+    const server = createServer(requestListener)
+
+    it('Should return a 500 for a malformed response', async () => {
+      const res = await request(server).get('/').send()
+      expect(res.status).toBe(500)
+    })
+  })
 })
 
 describe('Error handling - sync fetchCallback', () => {