diff --git a/influxdb/_dataframe_client.py b/influxdb/_dataframe_client.py
index 907db2cb..a4e6304f 100644
--- a/influxdb/_dataframe_client.py
+++ b/influxdb/_dataframe_client.py
@@ -219,7 +219,7 @@ def _to_dataframe(self, rs, dropna=True, data_frame_index=None):
             else:
                 key = (name, tuple(sorted(tags.items())))
             df = pd.DataFrame(data)
-            df.time = pd.to_datetime(df.time)
+            df.time = pd.to_datetime(df.time, format="mixed")
 
             if data_frame_index:
                 df.set_index(data_frame_index, inplace=True)