diff --git a/Kinetic_data_structures/include/CGAL/Kinetic/Delaunay_triangulation_2.h b/Kinetic_data_structures/include/CGAL/Kinetic/Delaunay_triangulation_2.h
index 50cecefa6c4..d146a5e183a 100644
--- a/Kinetic_data_structures/include/CGAL/Kinetic/Delaunay_triangulation_2.h
+++ b/Kinetic_data_structures/include/CGAL/Kinetic/Delaunay_triangulation_2.h
@@ -664,7 +664,7 @@ public:
     CGAL_assertion(mirror_flipped_edge == TDS_helper::mirror_edge(flipped_edge));
     //CGAL_postcondition(del_.is_face(face));
 
-    CGAL_assertion(mirror_index == face->nieghbor(index)->index(face));
+    CGAL_assertion(mirror_index == face->neighbor(index)->index(face));
     CGAL_assertion(mirror_face == face->neighbor(index));
 
     watcher_.post_flip(flipped_edge);