diff --git a/src/NCollection/NCollection_IndexedMap.hxx b/src/NCollection/NCollection_IndexedMap.hxx
index 6f4da8f4e9..875068d83c 100644
--- a/src/NCollection/NCollection_IndexedMap.hxx
+++ b/src/NCollection/NCollection_IndexedMap.hxx
@@ -44,7 +44,7 @@ public:
   //! STL-compliant typedef for key type
   typedef TheKeyType key_type;
 
-private:
+protected:
   //! Adaptation of the TListNode to the INDEXEDmap
   class IndexedMapNode : public NCollection_TListNode<TheKeyType>
   {