diff --git a/trick_source/sim_services/MonteCarlo/Makefile b/trick_source/sim_services/MonteCarlo/Makefile
index e38d53ca..a7b54f53 100644
--- a/trick_source/sim_services/MonteCarlo/Makefile
+++ b/trick_source/sim_services/MonteCarlo/Makefile
@@ -1,4 +1,4 @@
-
+TRICK_HOME := $(abspath $(dir $(lastword $(MAKEFILE_LIST)))../../..)
 include ${TRICK_HOME}/share/trick/makefiles/Makefile.common
 include ${TRICK_HOME}/share/trick/makefiles/Makefile.tricklib