diff --git a/sims/vcs/vcs.mk b/sims/vcs/vcs.mk
index 31784ad9..f816f102 100644
--- a/sims/vcs/vcs.mk
+++ b/sims/vcs/vcs.mk
@@ -57,5 +57,5 @@ VCS_PREPROC_DEFINES = \
 	+define+VCS
 
 ifndef USE_VPD
-PREPROC_DEFINES += +define+FSDB
+VCS_PREPROC_DEFINES += +define+FSDB
 endif