diff --git a/Kernel_23/doc/Kernel_23/CGAL/Bbox_2.h b/Kernel_23/doc/Kernel_23/CGAL/Bbox_2.h
index bd65ee37b04..5dc0277c497 100644
--- a/Kernel_23/doc/Kernel_23/CGAL/Bbox_2.h
+++ b/Kernel_23/doc/Kernel_23/CGAL/Bbox_2.h
@@ -82,6 +82,11 @@ returns a bounding box of `b` and `c`.
 */ 
 Bbox_2 operator+(const Bbox_2 &c) const; 
 
+/*!
+updates `b` to be the bounding box of `b` and `c` and returns itself.
+*/
+Bbox_2& operator+=(const Bbox_2 &c);
+
 /// @}
 
 }; /* end Bbox_2 */
diff --git a/Kernel_23/doc/Kernel_23/CGAL/Bbox_3.h b/Kernel_23/doc/Kernel_23/CGAL/Bbox_3.h
index cfa0ed6fa5b..2d763885de6 100644
--- a/Kernel_23/doc/Kernel_23/CGAL/Bbox_3.h
+++ b/Kernel_23/doc/Kernel_23/CGAL/Bbox_3.h
@@ -93,7 +93,12 @@ double max(int i) const;
 /*! 
 returns a bounding box of `b` and `c`. 
 */ 
-Bbox_3 operator+(const Bbox_3 &c) const; 
+Bbox_3 operator+(const Bbox_3 &c) const;
+
+/*!
+updates `b` to be the bounding box of `b` and `c` and returns itself.
+*/
+Bbox_3& operator+=(const Bbox_3 &c);
 
 /// @}
 
diff --git a/Kernel_23/include/CGAL/Bbox_2.h b/Kernel_23/include/CGAL/Bbox_2.h
index c5e187fb5f9..bedb38e7875 100644
--- a/Kernel_23/include/CGAL/Bbox_2.h
+++ b/Kernel_23/include/CGAL/Bbox_2.h
@@ -67,6 +67,7 @@ public:
   inline double     min BOOST_PREVENT_MACRO_SUBSTITUTION (int i) const;
 
   inline Bbox_2     operator+(const Bbox_2 &b) const;
+  inline Bbox_2&     operator+=(const Bbox_2 &b);
 
 };
 
@@ -138,6 +139,17 @@ Bbox_2::operator+(const Bbox_2 &b) const
                 (std::max)(ymax(), b.ymax()));
 }
 
+inline
+Bbox_2&
+Bbox_2::operator+=(const Bbox_2& b)
+{
+  rep[0] = (std::min)(xmin(), b.xmin());
+  rep[1] = (std::min)(ymin(), b.ymin());
+  rep[2] = (std::max)(xmax(), b.xmax());
+  rep[3] = (std::max)(ymax(), b.ymax());
+  return *this;
+}
+
 inline
 bool
 do_overlap(const Bbox_2 &bb1, const Bbox_2 &bb2)
diff --git a/Kernel_23/include/CGAL/Bbox_3.h b/Kernel_23/include/CGAL/Bbox_3.h
index fa1132c28f9..875bb79a1ac 100644
--- a/Kernel_23/include/CGAL/Bbox_3.h
+++ b/Kernel_23/include/CGAL/Bbox_3.h
@@ -66,6 +66,7 @@ public:
   inline double max BOOST_PREVENT_MACRO_SUBSTITUTION (int i) const;
 
   Bbox_3  operator+(const Bbox_3& b) const;
+  Bbox_3& operator+=(const Bbox_3& b);
 };
 
 inline
@@ -151,6 +152,19 @@ Bbox_3::operator+(const Bbox_3& b) const
                 (std::max)(zmax(), b.zmax()));
 }
 
+inline
+Bbox_3&
+Bbox_3::operator+=(const Bbox_3& b)
+{
+  rep[0] = (std::min)(xmin(), b.xmin());
+  rep[1] = (std::min)(ymin(), b.ymin());
+  rep[2] = (std::min)(zmin(), b.zmin());
+  rep[3] = (std::max)(xmax(), b.xmax());
+  rep[4] = (std::max)(ymax(), b.ymax());
+  rep[5] = (std::max)(zmax(), b.zmax());
+  return *this;
+}
+
 inline
 bool
 do_overlap(const Bbox_3& bb1, const Bbox_3& bb2)
diff --git a/Kernel_23/test/Kernel_23/test_bbox.cpp b/Kernel_23/test/Kernel_23/test_bbox.cpp
new file mode 100644
index 00000000000..28c63f89347
--- /dev/null
+++ b/Kernel_23/test/Kernel_23/test_bbox.cpp
@@ -0,0 +1,30 @@
+#include <CGAL/Simple_cartesian.h>
+#include <CGAL/Bbox_2.h>
+#include <CGAL/Bbox_3.h>
+
+typedef CGAL::Simple_cartesian<double> Kernel;
+typedef Kernel::Point_3 Point_3;
+typedef Kernel::Point_2 Point_2;
+
+int main()
+{
+  {
+  //Dimension 2
+  Point_2 p1(0,0), p2(1,-1.3);
+  CGAL::Bbox_2 b1 = p1.bbox(), b2=p2.bbox();
+  CGAL::Bbox_2 b3 = b1 + b2;
+  b1+=b2;
+  assert(b1==b3);
+  assert(CGAL::Bbox_2(0,-1.3,1,0) == b1);
+  }
+
+  {
+  //Dimension 3
+  Point_3 p1(0,0,0), p2(1,-1.3,1.5);
+  CGAL::Bbox_3 b1 = p1.bbox(), b2=p2.bbox();
+  CGAL::Bbox_3 b3 = b1 + b2;
+  b1+=b2;
+  assert(b1==b3);
+  assert(CGAL::Bbox_3(0,-1.3,0,1,0,1.5) == b1);
+  }
+}