diff --git a/Cartesian_kernel/include/CGAL/Cartesian/Sphere_3.h b/Cartesian_kernel/include/CGAL/Cartesian/Sphere_3.h
index 1e3f35b705c..3bdabf9f495 100644
--- a/Cartesian_kernel/include/CGAL/Cartesian/Sphere_3.h
+++ b/Cartesian_kernel/include/CGAL/Cartesian/Sphere_3.h
@@ -52,7 +52,7 @@ public:
   SphereC3(const Point_3 &center, const FT &squared_radius,
            const Orientation &o = COUNTERCLOCKWISE)
   {
-    CGAL_kernel_precondition( (squared_radius >= FT(0)) &&
+    CGAL_kernel_precondition( (squared_radius >= FT(0)) &
                               (o != COLLINEAR) );
 
     base = Rep(center, squared_radius, o);
diff --git a/Cartesian_kernel/include/CGAL/Cartesian/Vector_3.h b/Cartesian_kernel/include/CGAL/Cartesian/Vector_3.h
index df8d3d9cb24..ebd7657b531 100644
--- a/Cartesian_kernel/include/CGAL/Cartesian/Vector_3.h
+++ b/Cartesian_kernel/include/CGAL/Cartesian/Vector_3.h
@@ -187,7 +187,7 @@ inline
 const typename VectorC3<R>::FT &
 VectorC3<R>::cartesian(int i) const
 {
-  CGAL_kernel_precondition( (i>=0) && (i<3) );
+  CGAL_kernel_precondition( (i>=0) & (i<3) );
   if (i==0) return x();
   if (i==1) return y();
   return z();