diff --git a/include/trick/files_to_ICG.hh b/include/trick/files_to_ICG.hh
index 8f17b1b8..e3f59623 100644
--- a/include/trick/files_to_ICG.hh
+++ b/include/trick/files_to_ICG.hh
@@ -91,5 +91,6 @@
 #include "trick/Flag.h"
 #include "trick/wave_form.h"
 #include "trick/rand_generator.h"
+#include "trick/units_conv.h"
 
 #endif