diff --git a/include/uv.h b/include/uv.h
index 92cce2a152..d4566268b9 100644
--- a/include/uv.h
+++ b/include/uv.h
@@ -345,7 +345,7 @@ UV_EXTERN void uv_update_time(uv_loop_t*);
  *
  * Use uv_hrtime() if you need sub-millisecond granularity.
  */
-UV_EXTERN uint64_t uv_now(uv_loop_t*);
+UV_EXTERN uint64_t uv_now(const uv_loop_t*);
 
 /*
  * Get backend file descriptor. Only kqueue, epoll and event ports are
diff --git a/src/uv-common.c b/src/uv-common.c
index a7a3f74c18..96f66d6d33 100644
--- a/src/uv-common.c
+++ b/src/uv-common.c
@@ -384,7 +384,7 @@ void uv_stop(uv_loop_t* loop) {
 }
 
 
-uint64_t uv_now(uv_loop_t* loop) {
+uint64_t uv_now(const uv_loop_t* loop) {
   return loop->time;
 }