diff --git a/include/boost/intrusive_ptr.hpp b/include/boost/intrusive_ptr.hpp
index b612864..7db6dcf 100644
--- a/include/boost/intrusive_ptr.hpp
+++ b/include/boost/intrusive_ptr.hpp
@@ -128,7 +128,15 @@ public:
         return p_ != 0;
     }
 
-#else
+#elif defined(__MWERKS__) && BOOST_WORKAROUND(__MWERKS__, BOOST_TESTED_AT(0x3003))
+    typedef T * (this_type::*unspecified_bool_type)() const;
+    
+    operator unspecified_bool_type() const // never throws
+    {
+        return p_ == 0? 0: &this_type::get;
+    }
+
+#else 
 
     typedef T * this_type::*unspecified_bool_type;