diff --git a/Number_types/test/Number_types/Sqrt_extension.cpp b/Number_types/test/Number_types/Sqrt_extension.cpp
index ef35f423f46..27ff695cf67 100644
--- a/Number_types/test/Number_types/Sqrt_extension.cpp
+++ b/Number_types/test/Number_types/Sqrt_extension.cpp
@@ -8,6 +8,7 @@
 #include <CGAL/Test/_test_real_embeddable.h>
 #include <CGAL/Test/_test_coercion_traits.h>
 #include <CGAL/convert_to_bfi.h>
+#include <CGAL/Bigfloat_interval_traits.h>
 
 #include <cstdlib>
 #include <sstream>