diff --git a/src/node_constants.cc b/src/node_constants.cc
index 2aea278cb6..863a7c6ed9 100644
--- a/src/node_constants.cc
+++ b/src/node_constants.cc
@@ -110,6 +110,10 @@ void DefineConstants(Handle<Object> target) {
   NODE_DEFINE_CONSTANT(target, O_DIRECT);
 #endif
 
+#ifdef O_NONBLOCK
+  NODE_DEFINE_CONSTANT(target, O_NONBLOCK);
+#endif
+
 #ifdef S_IRWXU
   NODE_DEFINE_CONSTANT(target, S_IRWXU);
 #endif