diff --git a/src/kernel/libroot/posix/time/Jamfile b/src/kernel/libroot/posix/time/Jamfile
index 9d6b4b8d01..1bb0ffeca5 100644
--- a/src/kernel/libroot/posix/time/Jamfile
+++ b/src/kernel/libroot/posix/time/Jamfile
@@ -3,6 +3,7 @@ SubDir OBOS_TOP src kernel libroot posix time ;
 KernelMergeObject posix_time.o :
 	<$(SOURCE_GRIST)>asctime.c
 	<$(SOURCE_GRIST)>ctime.c
+	<$(SOURCE_GRIST)>difftime.c
 	<$(SOURCE_GRIST)>localtime.c
 	<$(SOURCE_GRIST)>mktime.c
 	<$(SOURCE_GRIST)>time.c
diff --git a/src/kernel/libroot/posix/time/difftime.c b/src/kernel/libroot/posix/time/difftime.c
new file mode 100644
index 0000000000..553d303160
--- /dev/null
+++ b/src/kernel/libroot/posix/time/difftime.c
@@ -0,0 +1,16 @@
+/* 
+** Copyright 2004, Axel Dörfler, axeld@pinc-software.de. All rights reserved.
+** Distributed under the terms of the Haiku License.
+*/
+
+
+#include <time.h>
+#include <SupportDefs.h>
+
+
+double
+difftime(time_t time1, time_t time2)
+{
+	return 1. * ((bigtime_t)time1 - (bigtime_t)time2);
+}
+