diff --git a/python/mxnet/ndarray/ndarray.py b/python/mxnet/ndarray/ndarray.py
index 78ec0b91f88d..4e6d0cdc929f 100644
--- a/python/mxnet/ndarray/ndarray.py
+++ b/python/mxnet/ndarray/ndarray.py
@@ -157,6 +157,11 @@ def waitall():
     """Wait for all async operations to finish in MXNet.
 
     This function is used for benchmarking only.
+    .. warning::
+    If your code has exceptions, `waitall` can cause silent failures.
+    For this reason you should avoid `waitall` in your code.
+    Use it only if you are confident that your code is error free.
+    Then make sure you call `wait_to_read` on all outputs after `waitall`.
     """
     check_call(_LIB.MXNDArrayWaitAll())