diff --git a/Packages/Triangulation_3/include/CGAL/Triangulation_data_structure_3.h b/Packages/Triangulation_3/include/CGAL/Triangulation_data_structure_3.h
index 0b35f7579a4..dbfced67ab8 100644
--- a/Packages/Triangulation_3/include/CGAL/Triangulation_data_structure_3.h
+++ b/Packages/Triangulation_3/include/CGAL/Triangulation_data_structure_3.h
@@ -32,6 +32,7 @@
 #include <CGAL/triple.h>
 #include <list.h>
 #include <map.h>
+#include <set.h>
 
 #include <CGAL/triangulation_assertions.h>
 #include <CGAL/Triangulation_short_names_3.h>