diff --git a/boost/serialization/strong_typedef.hpp b/boost/serialization/strong_typedef.hpp
--- a/boost/serialization/strong_typedef.hpp
+++ b/boost/serialization/strong_typedef.hpp
@@ -44,6 +44,7 @@
     operator const T&() const {return t;}                                                                        \
     operator T&() {return t;}                                                                                    \
     bool operator==(const D& rhs) const {return t == rhs.t;}                                                     \
+    bool operator==(const T& lhs) const {return t == lhs;}                                                       \
     bool operator<(const D& rhs) const {return t < rhs.t;}                                                       \
 };
 
