diff --git a/python/mxnet/rnn/io.py b/python/mxnet/rnn/io.py
index <HASH>..<HASH> 100644
--- a/python/mxnet/rnn/io.py
+++ b/python/mxnet/rnn/io.py
@@ -162,7 +162,7 @@ class BucketSentenceIter(DataIter):
             data = self.nddata[i][j:j+self.batch_size]
             label = self.ndlabel[i][j:j+self.batch_size]
 
-        return DataBatch([data], [label],
+        return DataBatch([data], [label], pad=0,
                          bucket_key=self.buckets[i],
                          provide_data=[(self.data_name, data.shape)],
                          provide_label=[(self.label_name, label.shape)])
Add pad param to DataBatch returned by BucketSentenceIter (#<I>)