diff --git a/CMakeLists.txt b/CMakeLists.txt
index 8ca301fdb17e43558accca871695055427f428a6..2685195e4e5ca856a4253eb5a82c87ba37fa02de 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -18,7 +18,7 @@ enable_language(CXX)
 enable_language(C)
 
 if (CM_ALL_USE_F08)
-    if (CM_ALL_FORTRAN)
+    if (NOT CM_ALL_FORTRAN)
         message(FATAL_ERROR "Flag for Fortran 08 MPI interface set, while Fortran interface is not enabled!")
     endif (CM_ALL_FORTRAN)
 endif (CM_ALL_USE_F08)