diff --git a/sys/vtimer/vtimer.c b/sys/vtimer/vtimer.c
index 531666e879413792ad3b7fbce066bbaa3a33fda0..4265baa19db3ce00a380f3d0b15a3142c0f6a3be 100644
--- a/sys/vtimer/vtimer.c
+++ b/sys/vtimer/vtimer.c
@@ -21,6 +21,9 @@
 #include <string.h>
 #include <inttypes.h>
 
+#define ENABLE_DEBUG    (0)
+#include "debug.h"
+
 #include "irq.h"
 #include "priority_queue.h"
 #include "timex.h"
@@ -32,8 +35,14 @@
 
 #include "vtimer.h"
 
-#define ENABLE_DEBUG    (0)
-#include "debug.h"
+
+#if ENABLE_DEBUG
+
+void vtimer_print_short_queue(void);
+void vtimer_print_long_queue(void);
+void vtimer_print(vtimer_t *t);
+
+#endif
 
 #define VTIMER_THRESHOLD 20UL
 #define VTIMER_BACKOFF 10UL