diff --git a/Include/structmember.h b/Include/structmember.h
index 91b23d5b5bb..e761f6d9683 100644
--- a/Include/structmember.h
+++ b/Include/structmember.h
@@ -37,7 +37,7 @@ typedef struct PyMemberDef {
 	/* Current version, use this */
 	char *name;
 	int type;
-	int offset;
+	Py_ssize_t offset;
 	int flags;
 	char *doc;
 } PyMemberDef;