diff --git a/src/frontend/spiceif.c b/src/frontend/spiceif.c
index 79654a83f..79148f9f2 100644
--- a/src/frontend/spiceif.c
+++ b/src/frontend/spiceif.c
@@ -47,6 +47,7 @@ they should be fairly 'safe'. However, ...
 CDHW*/
 
 #include "ngspice.h"
+#include "cktdefs.h"
 #include "cpdefs.h"
 #include "tskdefs.h" /* Is really needed ? */
 #include "ftedefs.h"