diff --git a/Arrangement_on_surface_2/include/CGAL/Arr_circular_arc_traits_2.h b/Arrangement_on_surface_2/include/CGAL/Arr_circular_arc_traits_2.h
index b0ea0982269..12ccbb1dc50 100644
--- a/Arrangement_on_surface_2/include/CGAL/Arr_circular_arc_traits_2.h
+++ b/Arrangement_on_surface_2/include/CGAL/Arr_circular_arc_traits_2.h
@@ -33,7 +33,6 @@
  */
 
 #include <CGAL/basic.h>
-#include <cassert>
 #include <CGAL/global_functions_on_circular_arcs_2.h>
 #include <CGAL/Arr_tags.h>
 
diff --git a/Arrangement_on_surface_2/include/CGAL/Arr_circular_line_arc_traits_2.h b/Arrangement_on_surface_2/include/CGAL/Arr_circular_line_arc_traits_2.h
index e60684ca361..80ffe24ec92 100644
--- a/Arrangement_on_surface_2/include/CGAL/Arr_circular_line_arc_traits_2.h
+++ b/Arrangement_on_surface_2/include/CGAL/Arr_circular_line_arc_traits_2.h
@@ -33,7 +33,6 @@
  */
 
 #include <CGAL/basic.h>
-#include <cassert>
 #include <boost/variant.hpp>
 #include <CGAL/Arr_tags.h>
 
diff --git a/Arrangement_on_surface_2/include/CGAL/Arr_line_arc_traits_2.h b/Arrangement_on_surface_2/include/CGAL/Arr_line_arc_traits_2.h
index 79282f79dec..c93dc791f39 100644
--- a/Arrangement_on_surface_2/include/CGAL/Arr_line_arc_traits_2.h
+++ b/Arrangement_on_surface_2/include/CGAL/Arr_line_arc_traits_2.h
@@ -33,8 +33,6 @@
  */
 
 #include <CGAL/basic.h>
-#include <cassert>
-
 #include <CGAL/tags.h>
 #include <CGAL/Arr_tags.h>
 #include <CGAL/global_functions_on_circular_arcs_2.h>
diff --git a/Circular_kernel_2/include/CGAL/Arr_circular_arc_traits.h b/Circular_kernel_2/include/CGAL/Arr_circular_arc_traits.h
index b32db28fe87..4735ed48056 100644
--- a/Circular_kernel_2/include/CGAL/Arr_circular_arc_traits.h
+++ b/Circular_kernel_2/include/CGAL/Arr_circular_arc_traits.h
@@ -26,7 +26,6 @@
 #define CGAL_CIRCULAR_KERNEL_CIRCULAR_ARC_TRAITS_H
 
 #include <CGAL/basic.h>
-#include <cassert>
 #include <CGAL/global_functions_on_circular_arcs_2.h>
 
 namespace CGAL {
diff --git a/Circular_kernel_2/include/CGAL/Arr_circular_arc_traits_checker.h b/Circular_kernel_2/include/CGAL/Arr_circular_arc_traits_checker.h
index 55d36f374fb..798d2300629 100644
--- a/Circular_kernel_2/include/CGAL/Arr_circular_arc_traits_checker.h
+++ b/Circular_kernel_2/include/CGAL/Arr_circular_arc_traits_checker.h
@@ -32,7 +32,7 @@
 // - It's not specific to circular arcs...
 
 #include <CGAL/basic.h>
-#include <cassert>
+#include <CGAL/kernel_assertions.h>
 #include <utility>
 
 namespace CGAL {
diff --git a/Circular_kernel_2/include/CGAL/Arr_circular_arc_traits_tracer.h b/Circular_kernel_2/include/CGAL/Arr_circular_arc_traits_tracer.h
index c7c75c195fc..a76f1081a53 100644
--- a/Circular_kernel_2/include/CGAL/Arr_circular_arc_traits_tracer.h
+++ b/Circular_kernel_2/include/CGAL/Arr_circular_arc_traits_tracer.h
@@ -26,7 +26,6 @@
 #define CGAL_CIRCULAR_KERNEL_CIRCULAR_ARC_TRAITS_TRACER_H
 
 #include <CGAL/basic.h>
-#include <cassert>
 #include <CGAL/Profile_counter.h>
 
 namespace CGAL {
diff --git a/Circular_kernel_2/include/CGAL/Arr_circular_line_arc_traits.h b/Circular_kernel_2/include/CGAL/Arr_circular_line_arc_traits.h
index 8d95e94c67e..5c1c05109a3 100644
--- a/Circular_kernel_2/include/CGAL/Arr_circular_line_arc_traits.h
+++ b/Circular_kernel_2/include/CGAL/Arr_circular_line_arc_traits.h
@@ -26,7 +26,6 @@
 #define CGAL_CIRCULAR_KERNEL_VARIANT_TRAITS_H
 
 #include <CGAL/basic.h>
-#include <cassert>
 #include <boost/variant.hpp>
 
 namespace CGAL {
diff --git a/Circular_kernel_2/include/CGAL/Arr_line_arc_traits.h b/Circular_kernel_2/include/CGAL/Arr_line_arc_traits.h
index 414401ea2f7..7d8b1a49f5c 100644
--- a/Circular_kernel_2/include/CGAL/Arr_line_arc_traits.h
+++ b/Circular_kernel_2/include/CGAL/Arr_line_arc_traits.h
@@ -26,12 +26,9 @@
 #define CGAL_CIRCULAR_KERNEL_LINE_ARC_TRAITS_H
 
 #include <CGAL/basic.h>
-#include <cassert>
 #include <CGAL/global_functions_on_circular_arcs_2.h>
 #include <CGAL/global_functions_on_line_arcs_2.h>
 
-
-
 namespace CGAL {
 
 // Traits class for CGAL::Arrangement_2 (and similar) based on a 
diff --git a/Circular_kernel_2/include/CGAL/Circular_kernel_2/Circular_arc_point_2.h b/Circular_kernel_2/include/CGAL/Circular_kernel_2/Circular_arc_point_2.h
index cc797add6c9..0d3907d2cd1 100644
--- a/Circular_kernel_2/include/CGAL/Circular_kernel_2/Circular_arc_point_2.h
+++ b/Circular_kernel_2/include/CGAL/Circular_kernel_2/Circular_arc_point_2.h
@@ -26,8 +26,6 @@
 #define CGAL_CIRCULAR_KERNEL_CIRCULAR_ARC_POINT_2_H
 
 #include <iostream>
-#include <cassert>
-
 #include <CGAL/Bbox_2.h>
 #include <CGAL/Interval_nt.h>
 #include <boost/type_traits/is_same.hpp>
diff --git a/Circular_kernel_2/include/CGAL/Filtered_bbox_circular_kernel_2/bbox_filtered_predicates.h b/Circular_kernel_2/include/CGAL/Filtered_bbox_circular_kernel_2/bbox_filtered_predicates.h
index 16cfc72e79a..039a0d32f70 100644
--- a/Circular_kernel_2/include/CGAL/Filtered_bbox_circular_kernel_2/bbox_filtered_predicates.h
+++ b/Circular_kernel_2/include/CGAL/Filtered_bbox_circular_kernel_2/bbox_filtered_predicates.h
@@ -25,7 +25,7 @@
 #ifndef CGAL_BBOX_FILTERED_PREDICATES_H  
 #define CGAL_BBOX_FILTERED_PREDICATES_H  
 
-#include <cassert>
+#include <CGAL/assertions.h>
 #include <CGAL/enum.h>
 #include <CGAL/Object.h>
 #include <CGAL/Bbox_2.h>
diff --git a/Circular_kernel_2/include/CGAL/Filtered_hexagon_circular_kernel_2/hexagon_filtered_predicates.h b/Circular_kernel_2/include/CGAL/Filtered_hexagon_circular_kernel_2/hexagon_filtered_predicates.h
index 61f4e0a6d91..d5dbc1492c1 100644
--- a/Circular_kernel_2/include/CGAL/Filtered_hexagon_circular_kernel_2/hexagon_filtered_predicates.h
+++ b/Circular_kernel_2/include/CGAL/Filtered_hexagon_circular_kernel_2/hexagon_filtered_predicates.h
@@ -25,8 +25,8 @@
 #ifndef CGAL_HEXAGON_FILTERED_PREDICATES_H  
 #define CGAL_HEXAGON_FILTERED_PREDICATES_H  
 
-#include <cassert>
 #include <fstream>
+#include <CGAL/assertions.h>
 #include <CGAL/Exact_predicates_inexact_constructions_kernel.h> 
 #include <CGAL/enum.h>
 #include <CGAL/Object.h>
diff --git a/Circular_kernel_3/include/CGAL/Circular_kernel_3/Circular_arc_point_3.h b/Circular_kernel_3/include/CGAL/Circular_kernel_3/Circular_arc_point_3.h
index 3fd626681d3..adda61dc1de 100644
--- a/Circular_kernel_3/include/CGAL/Circular_kernel_3/Circular_arc_point_3.h
+++ b/Circular_kernel_3/include/CGAL/Circular_kernel_3/Circular_arc_point_3.h
@@ -30,7 +30,6 @@
 #define CGAL_SPHERICAL_KERNEL_CIRCULAR_ARC_POINT_3_H
 
 #include <iostream>
-#include <cassert>
 
 //#include <CGAL/global_functions_on_roots_and_polynomials_2_2.h> 
 // fixme, devrait
diff --git a/Circular_kernel_3/include/CGAL/Circular_kernel_3/Circular_arc_point_on_reference_sphere_3.h b/Circular_kernel_3/include/CGAL/Circular_kernel_3/Circular_arc_point_on_reference_sphere_3.h
index 76a2c1d0215..de630aeb0fe 100644
--- a/Circular_kernel_3/include/CGAL/Circular_kernel_3/Circular_arc_point_on_reference_sphere_3.h
+++ b/Circular_kernel_3/include/CGAL/Circular_kernel_3/Circular_arc_point_on_reference_sphere_3.h
@@ -31,7 +31,6 @@
 #define CGAL_SPHERICAL_KERNEL_CIRCULAR_ARC_POINT_ON_REFERENCE_SPHERE_3_H
 
 #include <iostream>
-#include <cassert>
 
 #include <CGAL/Circular_arc_point_3.h>
 #include <CGAL/Circular_kernel_3/constant.h>
diff --git a/Envelope_3/include/CGAL/Envelope_3/Envelope_divide_and_conquer_3.h b/Envelope_3/include/CGAL/Envelope_3/Envelope_divide_and_conquer_3.h
index de6c488cce4..1f27b9ce853 100644
--- a/Envelope_3/include/CGAL/Envelope_3/Envelope_divide_and_conquer_3.h
+++ b/Envelope_3/include/CGAL/Envelope_3/Envelope_divide_and_conquer_3.h
@@ -25,7 +25,6 @@
 #define CGAL_ENVELOPE_USE_BFS_FACE_ORDER
 
 #include <iostream>
-#include <cassert>
 #include <list>
 #include <set>
 #include <vector>
diff --git a/Intersections_2/include/CGAL/Segment_2_Segment_2_intersection.h b/Intersections_2/include/CGAL/Segment_2_Segment_2_intersection.h
index f03f64fa65c..751d0af452b 100644
--- a/Intersections_2/include/CGAL/Segment_2_Segment_2_intersection.h
+++ b/Intersections_2/include/CGAL/Segment_2_Segment_2_intersection.h
@@ -29,15 +29,9 @@
 #include <CGAL/Point_2.h>
 #include <CGAL/kernel_assertions.h>
 #include <CGAL/number_utils.h>
-
-#include <cassert>
 #include <CGAL/predicates_on_points_2.h>
-
-
-
 #include <CGAL/Line_2.h>
 #include <CGAL/Line_2_Line_2_intersection.h>
-
 #include <CGAL/Object.h>
 
 CGAL_BEGIN_NAMESPACE
diff --git a/Kinetic_data_structures/include/CGAL/Polynomial/internal/Filtered_rational/Filtered_Sturm_sequence.h b/Kinetic_data_structures/include/CGAL/Polynomial/internal/Filtered_rational/Filtered_Sturm_sequence.h
index 56e38771702..09e0561b46f 100644
--- a/Kinetic_data_structures/include/CGAL/Polynomial/internal/Filtered_rational/Filtered_Sturm_sequence.h
+++ b/Kinetic_data_structures/include/CGAL/Polynomial/internal/Filtered_rational/Filtered_Sturm_sequence.h
@@ -25,8 +25,6 @@
 #include <CGAL/NT_converter.h>
 #include <CGAL/Polynomial/internal/Sign_variations_counter.h>
 
-//#include <cassert>
-
 CGAL_POLYNOMIAL_BEGIN_INTERNAL_NAMESPACE
 
 #define CGAL_POLYNOMIAL_NORMALIZE_GCD_IF_CONSTANT
diff --git a/Min_sphere_of_spheres_d/include/CGAL/Min_sphere_of_spheres_d.h b/Min_sphere_of_spheres_d/include/CGAL/Min_sphere_of_spheres_d.h
index 7deeb676fb8..f7f8e896e58 100644
--- a/Min_sphere_of_spheres_d/include/CGAL/Min_sphere_of_spheres_d.h
+++ b/Min_sphere_of_spheres_d/include/CGAL/Min_sphere_of_spheres_d.h
@@ -22,7 +22,6 @@
 #define CGAL_MINIBALL_MINIBALL
 
 #include <CGAL/Min_sphere_of_spheres_d/Min_sphere_of_spheres_d_configure.h>
-#include <cassert>
 #include <cstdlib>                 // for std::rand()
 #include <cmath>
 #include <vector>
diff --git a/Number_types/include/CGAL/simplest_rational_in_interval.h b/Number_types/include/CGAL/simplest_rational_in_interval.h
index 79b2811695e..9bf73e09dd6 100644
--- a/Number_types/include/CGAL/simplest_rational_in_interval.h
+++ b/Number_types/include/CGAL/simplest_rational_in_interval.h
@@ -24,14 +24,11 @@
 #ifndef CGAL_SIMPLEST_RATIONAL_IN_INTERVAL_H
 #define CGAL_SIMPLEST_RATIONAL_IN_INTERVAL_H
 
-
 #include <CGAL/number_type_basic.h>
 #include <CGAL/to_rational.h>
-#include <cassert>
 #include <climits>
 #include <cmath>
 
-
 CGAL_BEGIN_NAMESPACE
 
 /* simplest_rational_in_interval(x,y) returns the rational number with
diff --git a/OpenNL/include/CGAL/OpenNL/bicgstab.h b/OpenNL/include/CGAL/OpenNL/bicgstab.h
index 87cfbf57bb0..82e3f953044 100644
--- a/OpenNL/include/CGAL/OpenNL/bicgstab.h
+++ b/OpenNL/include/CGAL/OpenNL/bicgstab.h
@@ -38,11 +38,11 @@
 #define __OPENNL_BICGSTAB__
 
 #include <CGAL/OpenNL/blas.h>
+#include <CGAL/assertions.h>
 
 #include <cmath>
 #include <cfloat>
 #include <climits>
-#include <cassert>
 
 namespace OpenNL {
 
diff --git a/OpenNL/include/CGAL/OpenNL/conjugate_gradient.h b/OpenNL/include/CGAL/OpenNL/conjugate_gradient.h
index 2f60e3dacb0..92467899914 100644
--- a/OpenNL/include/CGAL/OpenNL/conjugate_gradient.h
+++ b/OpenNL/include/CGAL/OpenNL/conjugate_gradient.h
@@ -38,11 +38,11 @@
 #define __OPENNL_CONJUGATE_GRADIENT__
 
 #include <CGAL/OpenNL/blas.h>
+#include <CGAL/assertions.h>
 
 #include <cmath>
 #include <cfloat>
 #include <climits>
-#include <cassert>
 
 namespace OpenNL {
 
diff --git a/OpenNL/include/CGAL/OpenNL/full_vector.h b/OpenNL/include/CGAL/OpenNL/full_vector.h
index 6b3556b3f89..308a57d05e8 100644
--- a/OpenNL/include/CGAL/OpenNL/full_vector.h
+++ b/OpenNL/include/CGAL/OpenNL/full_vector.h
@@ -37,9 +37,9 @@
 #define __OPENNL_FULL_VECTOR__
 
 #include <CGAL/OpenNL/blas.h>
+#include <CGAL/assertions.h>
 
 #include <cstdlib>
-#include <cassert>
 
 namespace OpenNL {
 
diff --git a/OpenNL/include/CGAL/OpenNL/preconditioner.h b/OpenNL/include/CGAL/OpenNL/preconditioner.h
index 55e0953aa42..71fc636abc9 100644
--- a/OpenNL/include/CGAL/OpenNL/preconditioner.h
+++ b/OpenNL/include/CGAL/OpenNL/preconditioner.h
@@ -38,7 +38,7 @@
 #include <CGAL/OpenNL/sparse_matrix.h>
 #include <CGAL/OpenNL/full_vector.h>
 
-#include <cassert>
+#include <CGAL/assertions.h>
 
 namespace OpenNL {
 
diff --git a/OpenNL/include/CGAL/OpenNL/sparse_matrix.h b/OpenNL/include/CGAL/OpenNL/sparse_matrix.h
index 82346c209e9..8f8dc174412 100644
--- a/OpenNL/include/CGAL/OpenNL/sparse_matrix.h
+++ b/OpenNL/include/CGAL/OpenNL/sparse_matrix.h
@@ -35,10 +35,10 @@
 #define __OPENNL_SPARSE_MATRIX__
 
 #include <CGAL/OpenNL/full_vector.h>
+#include <CGAL/assertions.h>
 
 #include <vector>
 #include <cstdlib>
-#include <cassert>
 
 namespace OpenNL {
 
diff --git a/Partition_2/include/CGAL/Partition_2/Partition_vertex_map.h b/Partition_2/include/CGAL/Partition_2/Partition_vertex_map.h
index 047dd27b95f..a2a6e4b7fea 100644
--- a/Partition_2/include/CGAL/Partition_2/Partition_vertex_map.h
+++ b/Partition_2/include/CGAL/Partition_2/Partition_vertex_map.h
@@ -23,7 +23,7 @@
 #include <map>
 #include <iostream>
 #include <CGAL/circulator.h>
-#include <cassert>
+#include <CGAL/assertions.h>
 
 #include <sstream>
 
diff --git a/STL_Extension/src/CGAL/assertions.cpp b/STL_Extension/src/CGAL/assertions.cpp
index 3104feb84d9..f14b49938f1 100644
--- a/STL_Extension/src/CGAL/assertions.cpp
+++ b/STL_Extension/src/CGAL/assertions.cpp
@@ -27,19 +27,9 @@
 
 #include <cstdlib>
 #include <iostream>
-#include <cassert>
 
 CGAL_BEGIN_NAMESPACE
 
-// not_implemented function
-// ------------------------
-void
-not_implemented()
-{
-    assert( false);
-}
-
-
 namespace {
 
 // behaviour variables
diff --git a/Surface_mesh_parameterization/include/CGAL/Taucs_solver_traits.h b/Surface_mesh_parameterization/include/CGAL/Taucs_solver_traits.h
index 3b0566f7e0b..f56518cf382 100644
--- a/Surface_mesh_parameterization/include/CGAL/Taucs_solver_traits.h
+++ b/Surface_mesh_parameterization/include/CGAL/Taucs_solver_traits.h
@@ -32,8 +32,6 @@
 
 #include <boost/shared_ptr.hpp>
 
-#include <cassert>
-
 CGAL_BEGIN_NAMESPACE
 
 
diff --git a/Width_3/include/CGAL/width_assertions.h b/Width_3/include/CGAL/width_assertions.h
index bc2c8f0a9dc..8201bbfaf08 100644
--- a/Width_3/include/CGAL/width_assertions.h
+++ b/Width_3/include/CGAL/width_assertions.h
@@ -109,13 +109,6 @@
  #define DEBUGPRINT(doit,msg,var)
  #define DEBUGMSG(doit,msg)
  #define INFOMSG(doit,msg)
-// #define NDEBUG // discard assertions. Changed since it violates std: L.K.
 #endif
 
-#include <cassert>
-
 #endif //#WIDTH_DEBUG_H
-
-
-
-