diff --git a/core/net/rpl/rpl-dag.c b/core/net/rpl/rpl-dag.c
index 53ba956fa..5bc15d7af 100644
--- a/core/net/rpl/rpl-dag.c
+++ b/core/net/rpl/rpl-dag.c
@@ -948,6 +948,7 @@ rpl_join_instance(uip_ipaddr_t *from, rpl_dio_t *dio)
   }
 }
 
+#if RPL_MAX_DAG_PER_INSTANCE > 1
 /*---------------------------------------------------------------------------*/
 void
 rpl_add_dag(uip_ipaddr_t *from, rpl_dio_t *dio)
@@ -1027,6 +1028,7 @@ rpl_add_dag(uip_ipaddr_t *from, rpl_dio_t *dio)
   rpl_process_parent_event(instance, p);
   p->dtsn = dio->dtsn;
 }
+#endif /* RPL_MAX_DAG_PER_INSTANCE > 1 */
 
 /*---------------------------------------------------------------------------*/
 static void
@@ -1214,9 +1216,14 @@ rpl_process_dio(uip_ipaddr_t *from, rpl_dio_t *dio)
   }
 
   if(dag == NULL) {
+#if RPL_MAX_DAG_PER_INSTANCE > 1
     PRINTF("RPL: Adding new DAG to known instance.\n");
     rpl_add_dag(from, dio);
     return;
+#else /* RPL_MAX_DAG_PER_INSTANCE > 1 */
+    PRINTF("RPL: Only one instance supported.\n");
+    return;
+#endif /* RPL_MAX_DAG_PER_INSTANCE > 1 */
   }