diff --git a/Nef_3/include/CGAL/Nef_nary_intersection_3.h b/Nef_3/include/CGAL/Nef_nary_intersection_3.h
index 70fc5791fae..5178705dc2f 100644
--- a/Nef_3/include/CGAL/Nef_nary_intersection_3.h
+++ b/Nef_3/include/CGAL/Nef_nary_intersection_3.h
@@ -52,7 +52,8 @@ class Nef_nary_intersection_3 {
   }
 
   Polyhedron get_intersection() {
-
+    if (queue.empty())
+      return empty;
     while(queue.size() > 1)
       intersect();
     inserted = 0;
diff --git a/Nef_3/include/CGAL/Nef_nary_union_3.h b/Nef_3/include/CGAL/Nef_nary_union_3.h
index ecbbae2db59..c8663bb911b 100644
--- a/Nef_3/include/CGAL/Nef_nary_union_3.h
+++ b/Nef_3/include/CGAL/Nef_nary_union_3.h
@@ -52,7 +52,8 @@ class Nef_nary_union_3 {
   }
 
   Polyhedron get_union() {
-
+    if (queue.empty())
+      return empty;
     while(queue.size() > 1)
       unite();
     inserted = 0;