diff --git a/include/boost/utility/enable_if.hpp b/include/boost/utility/enable_if.hpp
index 4a0a408..53a4f25 100644
--- a/include/boost/utility/enable_if.hpp
+++ b/include/boost/utility/enable_if.hpp
@@ -66,27 +66,51 @@ namespace boost
 {
  
   template <bool B, class T = void>
-  struct enable_if {
+  struct enable_if_c {
     typedef T type;
   };
 
   template <class T>
-  struct enable_if<false, T> {};
+  struct enable_if_c<false, T> {};
 
+  template <class Cond, class T = void> 
+  struct enable_if : public enable_if_c<Cond::value, T> {};
 
   template <bool B, class T>
-  struct enable_if_lazy {
+  struct lazy_enable_if_c {
     typedef typename T::type type;
   };
 
   template <class T>
-  struct enable_if_lazy<false, T> {};
+  struct lazy_enable_if_c<false, T> {};
+
+  template <class Cond, class T> 
+  struct lazy_enable_if : public lazy_enable_if_c<Cond::value, T> {};
+
 
   template <bool B, class T = void>
-  struct disable_if: public enable_if< !B, T> {};
+  struct disable_if_c {
+    typedef T type;
+  };
+
+  template <class T>
+  struct disable_if_c<true, T> {};
+
+  template <class Cond, class T = void> 
+  struct disable_if : public disable_if_c<Cond::value, T> {};
 
   template <bool B, class T>
-  struct disable_if_lazy: public enable_if_lazy< !B, T> {};
+  struct lazy_disable_if_c {
+    typedef typename T::type type;
+  };
+
+  template <class T>
+  struct lazy_disable_if_c<true, T> {};
+
+  template <class Cond, class T> 
+  struct lazy_disable_if : public lazy_disable_if_c<Cond::value, T> {};
+
+
   
 } // namespace boost