diff --git a/json_logging/dto.py b/json_logging/dto.py
index 4cf39a8..9c349d0 100644
--- a/json_logging/dto.py
+++ b/json_logging/dto.py
@@ -1,4 +1,4 @@
-from datetime import datetime
+from datetime import datetime, timezone
 
 from json_logging import util
 
@@ -32,14 +32,14 @@ class DefaultRequestResponseDTO(RequestResponseDTOBase):
 
     def __init__(self, request, **kwargs):
         super(DefaultRequestResponseDTO, self).__init__(request, **kwargs)
-        utcnow = datetime.utcnow()
+        utcnow = datetime.now(timezone.utc).replace(tzinfo=None)
         self._request_start = utcnow
         self["request_received_at"] = util.iso_time_format(utcnow)
 
     # noinspection PyAttributeOutsideInit
     def on_request_complete(self, response):
         super(DefaultRequestResponseDTO, self).on_request_complete(response)
-        utcnow = datetime.utcnow()
+        utcnow = datetime.now(timezone.utc).replace(tzinfo=None)
         time_delta = utcnow - self._request_start
         self["response_time_ms"] = int(time_delta.total_seconds()) * 1000 + int(time_delta.microseconds / 1000)
         self["response_sent_at"] = util.iso_time_format(utcnow)
diff --git a/json_logging/formatters.py b/json_logging/formatters.py
index d0a428a..9c3417d 100644
--- a/json_logging/formatters.py
+++ b/json_logging/formatters.py
@@ -1,7 +1,7 @@
 import logging
 import sys
 import traceback
-from datetime import datetime
+from datetime import datetime, timezone
 
 import json_logging
 
@@ -61,7 +61,7 @@ def format(self, record):
         return json_logging.JSON_SERIALIZER(log_object)
 
     def _format_log_object(self, record, request_util):
-        utcnow = datetime.utcnow()
+        utcnow = datetime.now(timezone.utc).replace(tzinfo=None)
 
         base_obj = {
             "written_at": json_logging.util.iso_time_format(utcnow),