diff --git a/lib/kafs/afssysdefs.h b/lib/kafs/afssysdefs.h
index efc126084..e0c696076 100644
--- a/lib/kafs/afssysdefs.h
+++ b/lib/kafs/afssysdefs.h
@@ -90,6 +90,10 @@
 #endif
 #endif /* __FreeBSD__ */
 
+#ifdef __DragonFly__
+#define AFS_SYSCALL 339
+#endif
+
 #ifdef __OpenBSD__
 #define AFS_SYSCALL 208
 #endif