diff --git a/NewKernel_d/include/CGAL/NewKernel_d/Lazy_cartesian.h b/NewKernel_d/include/CGAL/NewKernel_d/Lazy_cartesian.h
index 26741caf72a..6e6b496840e 100644
--- a/NewKernel_d/include/CGAL/NewKernel_d/Lazy_cartesian.h
+++ b/NewKernel_d/include/CGAL/NewKernel_d/Lazy_cartesian.h
@@ -15,6 +15,7 @@
 #include <CGAL/basic.h>
 #include <CGAL/algorithm.h>
 #include <CGAL/Lazy.h>
+#include <CGAL/Lazy_exact_nt.h>
 #include <CGAL/Default.h>
 #include <CGAL/NewKernel_d/Filtered_predicate2.h>
 #include <CGAL/iterator_from_indices.h>
diff --git a/Straight_skeleton_2/include/CGAL/Straight_skeleton_2/Straight_skeleton_builder_traits_2_aux.h b/Straight_skeleton_2/include/CGAL/Straight_skeleton_2/Straight_skeleton_builder_traits_2_aux.h
index 37a9307dcaf..d521dc4257c 100644
--- a/Straight_skeleton_2/include/CGAL/Straight_skeleton_2/Straight_skeleton_builder_traits_2_aux.h
+++ b/Straight_skeleton_2/include/CGAL/Straight_skeleton_2/Straight_skeleton_builder_traits_2_aux.h
@@ -25,6 +25,7 @@
 #include <CGAL/tags.h>
 #include <CGAL/Uncertain.h>
 #include <CGAL/Unfiltered_predicate_adaptor.h>
+#include <CGAL/Lazy_exact_nt.h>
 
 #include <boost/tuple/tuple.hpp>
 #include <boost/optional/optional.hpp>
diff --git a/Surface_mesher/test/Surface_mesher/implicit_surface_mesher_test.cpp b/Surface_mesher/test/Surface_mesher/implicit_surface_mesher_test.cpp
index 31dd6c11652..374c5b6941c 100644
--- a/Surface_mesher/test/Surface_mesher/implicit_surface_mesher_test.cpp
+++ b/Surface_mesher/test/Surface_mesher/implicit_surface_mesher_test.cpp
@@ -1,6 +1,7 @@
 #include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
 #include <CGAL/Cartesian.h>
 #include <CGAL/Filtered_kernel.h>
+#include <CGAL/Lazy_exact_nt.h>
 
 #include <CGAL/make_surface_mesh.h>