diff --git a/reactos/Makefile b/reactos/Makefile
index 453ea6ba60f..52c59dd049c 100644
--- a/reactos/Makefile
+++ b/reactos/Makefile
@@ -112,6 +112,10 @@
 #        will go from 80 to 40MB, memory usage from 58 to 38MB and the install CD
 #        from 18 to 13MB. The variable defaults to no.
 #
+#    ROS_GENERATE_RSYM
+#        This variable controls generation of RSYM symbol data. The value can be
+#        either yes (to generate symbol data) or no. The variable defaults to yes.
+#
 #    ROS_RBUILDFLAGS
 #        Pass parameters to rbuild.
 #            -v           Be verbose.