diff --git a/Intersections_2/include/CGAL/Intersections_2/Iso_rectangle_2_Iso_rectangle_2.h b/Intersections_2/include/CGAL/Intersections_2/Iso_rectangle_2_Iso_rectangle_2.h
index 0b73db82b88..35013ea0e5e 100644
--- a/Intersections_2/include/CGAL/Intersections_2/Iso_rectangle_2_Iso_rectangle_2.h
+++ b/Intersections_2/include/CGAL/Intersections_2/Iso_rectangle_2_Iso_rectangle_2.h
@@ -20,6 +20,7 @@
 
 #include <CGAL/Iso_rectangle_2.h>
 #include <CGAL/Intersection_traits_2.h>
+#include <CGAL/Rational_traits.h>
 
 namespace CGAL {