diff --git a/include/boost/intrusive/detail/list_iterator.hpp b/include/boost/intrusive/detail/list_iterator.hpp
index 77c9fa6..6af4841 100644
--- a/include/boost/intrusive/detail/list_iterator.hpp
+++ b/include/boost/intrusive/detail/list_iterator.hpp
@@ -34,7 +34,7 @@ namespace intrusive {
 template<class ValueTraits, bool IsConst>
 class list_iterator
 {
-   protected:
+   private:
    typedef iiterator
       <ValueTraits, IsConst, std::bidirectional_iterator_tag> types_t;
 
diff --git a/include/boost/intrusive/detail/slist_iterator.hpp b/include/boost/intrusive/detail/slist_iterator.hpp
index 80a6fef..1699064 100644
--- a/include/boost/intrusive/detail/slist_iterator.hpp
+++ b/include/boost/intrusive/detail/slist_iterator.hpp
@@ -36,7 +36,7 @@ namespace intrusive {
 template<class ValueTraits, bool IsConst>
 class slist_iterator
 {
-   protected:
+   private:
    typedef iiterator
       <ValueTraits, IsConst, std::forward_iterator_tag> types_t;