diff --git a/qmake/doc/src/qmake-manual.qdoc b/qmake/doc/src/qmake-manual.qdoc
index 5a7a6002103..07a0246124a 100644
--- a/qmake/doc/src/qmake-manual.qdoc
+++ b/qmake/doc/src/qmake-manual.qdoc
@@ -1153,6 +1153,8 @@
     Specifies project configuration and compiler options. The values are
     recognized internally by qmake and have special meaning.
 
+    \note The values are case-sensitive.
+
     The following \c CONFIG values control compiler and linker flags:
 
     \table