diff --git a/Intersections_3/include/CGAL/Intersections_3/internal/Bbox_3_Segment_3_do_intersect.h b/Intersections_3/include/CGAL/Intersections_3/internal/Bbox_3_Segment_3_do_intersect.h
index 8015f82c464..99f1e2ee078 100644
--- a/Intersections_3/include/CGAL/Intersections_3/internal/Bbox_3_Segment_3_do_intersect.h
+++ b/Intersections_3/include/CGAL/Intersections_3/internal/Bbox_3_Segment_3_do_intersect.h
@@ -25,6 +25,7 @@
 
 #include <CGAL/disable_warnings.h>
 
+#include <CGAL/number_utils.h>
 #include <CGAL/Segment_3.h>
 #include <CGAL/Bbox_3.h>
 #include <CGAL/Kernel/Same_uncertainty.h>