diff --git a/Lib/test/test_bytes.py b/Lib/test/test_bytes.py
index c45c69f3f22..c2fe2cc2542 100644
--- a/Lib/test/test_bytes.py
+++ b/Lib/test/test_bytes.py
@@ -982,14 +982,14 @@ class BytesTest(BaseBytesTest, unittest.TestCase):
     type2test = bytes
 
     def test__bytes__(self):
-        foo = b'foo'
+        foo = b'foo\x00bar'
         self.assertEqual(foo.__bytes__(), foo)
         self.assertEqual(type(foo.__bytes__()), self.type2test)
 
         class bytes_subclass(bytes):
             pass
 
-        bar = bytes_subclass(b'bar')
+        bar = bytes_subclass(b'bar\x00foo')
         self.assertEqual(bar.__bytes__(), bar)
         self.assertEqual(type(bar.__bytes__()), self.type2test)
 
diff --git a/Objects/bytesobject.c b/Objects/bytesobject.c
index 13f94b4c82f..27f766bef6e 100644
--- a/Objects/bytesobject.c
+++ b/Objects/bytesobject.c
@@ -1701,7 +1701,7 @@ bytes___bytes___impl(PyBytesObject *self)
         return (PyObject *)self;
     }
     else {
-        return PyBytes_FromString(self->ob_sval);
+        return PyBytes_FromStringAndSize(self->ob_sval, Py_SIZE(self));
     }
 }