diff --git a/core/sys/stimer.c b/core/sys/stimer.c
index b300afb3d..4307b8022 100644
--- a/core/sys/stimer.c
+++ b/core/sys/stimer.c
@@ -42,7 +42,7 @@
  *
  * Author: Adam Dunkels <adam@sics.se>, Nicolas Tsiftes <nvt@sics.se>
  *
- * $Id: stimer.c,v 1.2 2008/11/05 19:34:36 nvt-se Exp $
+ * $Id: stimer.c,v 1.3 2010/03/15 15:53:57 joxe Exp $
  */
 
 #include "contiki-conf.h"
@@ -142,6 +142,23 @@ stimer_remaining(struct stimer *t)
 {
   return t->start + t->interval - clock_seconds();
 }
+/*---------------------------------------------------------------------------*/
+/**
+ * The time elapsed since the timer started
+ *
+ * This function returns the time elapsed.
+ *
+ * \param t A pointer to the timer
+ *
+ * \return The time elapsed since the last start of the timer
+ *
+ */
+unsigned long
+stimer_elapsed(struct stimer *t)
+{
+  return clock_seconds() - t->start;
+}
+
 /*---------------------------------------------------------------------------*/
 
 /** @} */
diff --git a/core/sys/stimer.h b/core/sys/stimer.h
index 11bd1dee6..84279f711 100644
--- a/core/sys/stimer.h
+++ b/core/sys/stimer.h
@@ -64,7 +64,7 @@
  *
  * Author: Adam Dunkels <adam@sics.se>, Nicolas Tsiftes <nvt@sics.se>
  *
- * $Id: stimer.h,v 1.3 2009/03/01 09:31:43 adamdunkels Exp $
+ * $Id: stimer.h,v 1.4 2010/03/15 15:53:57 joxe Exp $
  */
 #ifndef __STIMER_H__
 #define __STIMER_H__
@@ -89,6 +89,7 @@ void stimer_reset(struct stimer *t);
 void stimer_restart(struct stimer *t);
 int stimer_expired(struct stimer *t);
 unsigned long stimer_remaining(struct stimer *t);
+unsigned long stimer_elapsed(struct stimer *t);
 
 
 #endif /* __STIMER_H__ */