diff --git a/include/boost/graph/isomorphism.hpp b/include/boost/graph/isomorphism.hpp
index d5217e33..6d285bfa 100644
--- a/include/boost/graph/isomorphism.hpp
+++ b/include/boost/graph/isomorphism.hpp
@@ -64,6 +64,7 @@ namespace boost {
           } else
             if (edge(f[*i], j, g2).second)
               return false;
+      return true;
     }