diff --git a/include/boost/phoenix/core.hpp b/include/boost/phoenix/core.hpp
index 272d046..9c836f5 100644
--- a/include/boost/phoenix/core.hpp
+++ b/include/boost/phoenix/core.hpp
@@ -10,6 +10,7 @@
 #include <boost/phoenix/version.hpp>
 #include <boost/phoenix/core/limits.hpp>
 #include <boost/phoenix/core/actor.hpp>
+#include <boost/phoenix/core/debug.hpp>
 #include <boost/phoenix/core/is_actor.hpp>
 #include <boost/phoenix/core/argument.hpp>
 #include <boost/phoenix/core/value.hpp>