diff --git a/CHANGELOG.md b/CHANGELOG.md
index 53fb3e3..693b1af 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@
 ## Unreleased
 
 -   Added `PyAwaitable_AddExpr`.
+-   Fix assertion failures when running in debug mode.
 
 ## [2.0.1] - 2025-06-15
 
diff --git a/src/_pyawaitable/awaitable.c b/src/_pyawaitable/awaitable.c
index a415603..76ba891 100644
--- a/src/_pyawaitable/awaitable.c
+++ b/src/_pyawaitable/awaitable.c
@@ -160,7 +160,7 @@ PyAwaitable_AddAwait(
 )
 {
     PyAwaitableObject *aw = (PyAwaitableObject *) self;
-    assert(Py_IS_TYPE(Py_TYPE(self), PyAwaitable_GetType()));
+    assert(Py_IS_TYPE(self, PyAwaitable_GetType()));
     if (coro == NULL) {
         PyErr_SetString(
             PyExc_ValueError,
@@ -231,7 +231,7 @@ _PyAwaitable_API(int)
 PyAwaitable_DeferAwait(PyObject * awaitable, PyAwaitable_Defer cb)
 {
     PyAwaitableObject *aw = (PyAwaitableObject *) awaitable;
-    assert(Py_IS_TYPE(Py_TYPE(awaitable), PyAwaitable_GetType()));
+    assert(Py_IS_TYPE(awaitable, PyAwaitable_GetType()));
     pyawaitable_callback *aw_c = PyMem_Malloc(sizeof(pyawaitable_callback));
     if (aw_c == NULL) {
         PyErr_NoMemory();
@@ -256,7 +256,7 @@ _PyAwaitable_API(int)
 PyAwaitable_SetResult(PyObject * awaitable, PyObject * result)
 {
     PyAwaitableObject *aw = (PyAwaitableObject *) awaitable;
-    assert(Py_IS_TYPE(Py_TYPE(awaitable), PyAwaitable_GetType()));
+    assert(Py_IS_TYPE(awaitable, PyAwaitable_GetType()));
     aw->aw_result = Py_NewRef(result);
     return 0;
 }