diff --git a/brozzler/__init__.py b/brozzler/__init__.py
index ccfaacd..c97835f 100644
--- a/brozzler/__init__.py
+++ b/brozzler/__init__.py
@@ -159,7 +159,7 @@ class ThreadExceptionGate:
     def queue_exception(self, e):
         with self.lock:
             if self.pending_exception:
-                self.logger.warn(
+                self.logger.warning(
                         '%r already pending for thread %r, discarding %r',
                         self.pending_exception, self.thread, e)
             else:
diff --git a/brozzler/chrome.py b/brozzler/chrome.py
index 5928586..c70296f 100644
--- a/brozzler/chrome.py
+++ b/brozzler/chrome.py
@@ -223,7 +223,7 @@ class Chrome:
                 raise
             except Exception as e:
                 if time.time() - self._last_warning > 30:
-                    self.logger.warn(
+                    self.logger.warning(
                             'problem with %s (will keep trying until timeout '
                             'of %d seconds): %s', json_url, timeout_sec, e)
                     self._last_warning = time.time()
@@ -294,7 +294,7 @@ class Chrome:
                                 'chrome pid %s exited normally',
                                 self.chrome_process.pid)
                     else:
-                        self.logger.warn(
+                        self.logger.warning(
                                 'chrome pid %s exited with nonzero status %s',
                                 self.chrome_process.pid, status)
 
@@ -305,13 +305,13 @@ class Chrome:
                     return
                 time.sleep(0.5)
 
-            self.logger.warn(
+            self.logger.warning(
                     'chrome pid %s still alive %.1f seconds after sending '
                     'SIGTERM, sending SIGKILL', self.chrome_process.pid,
                     time.time() - t0)
             os.killpg(self.chrome_process.pid, signal.SIGKILL)
             status = self.chrome_process.wait()
-            self.logger.warn(
+            self.logger.warning(
                     'chrome pid %s reaped (status=%s) after killing with '
                     'SIGKILL', self.chrome_process.pid, status)
 
diff --git a/brozzler/cli.py b/brozzler/cli.py
index 188d591..4b0bd76 100644
--- a/brozzler/cli.py
+++ b/brozzler/cli.py
@@ -627,7 +627,7 @@ def brozzler_purge(argv=None):
             sys.exit(1)
         if job.status == 'ACTIVE':
             if args.force:
-                logging.warn(
+                logging.warning(
                         'job %s has status ACTIVE, purging anyway because '
                         '--force was supplied', job_id)
             else:
@@ -644,7 +644,7 @@ def brozzler_purge(argv=None):
             sys.exit(1)
         if site.status == 'ACTIVE':
             if args.force:
-                logging.warn(
+                logging.warning(
                         'site %s has status ACTIVE, purging anyway because '
                         '--force was supplied', site_id)
             else:
@@ -712,7 +712,7 @@ def brozzler_list_captures(argv=None):
 
     if args.url_or_sha1[:5] == 'sha1:':
         if args.prefix:
-            logging.warn(
+            logging.warning(
                     'ignoring supplied --prefix option which does not apply '
                     'to lookup by sha1')
         # assumes it's already base32 (XXX could detect if hex and convert)
diff --git a/brozzler/easy.py b/brozzler/easy.py
index 83cf1ba..dd98884 100644
--- a/brozzler/easy.py
+++ b/brozzler/easy.py
@@ -260,7 +260,7 @@ class BrozzlerEasyController:
             state_strs.append(str(th))
             stack = traceback.format_stack(sys._current_frames()[th.ident])
             state_strs.append(''.join(stack))
-        logging.warn('dumping state (caught signal {})\n{}'.format(
+        logging.warning('dumping state (caught signal {})\n{}'.format(
             signum, '\n'.join(state_strs)))
 
 def main(argv=None):
diff --git a/brozzler/frontier.py b/brozzler/frontier.py
index 3826abf..0e3b777 100644
--- a/brozzler/frontier.py
+++ b/brozzler/frontier.py
@@ -138,7 +138,7 @@ class RethinkDbFrontier:
         sites = []
         for i in range(result["replaced"]):
             if result["changes"][i]["old_val"]["claimed"]:
-                self.logger.warn(
+                self.logger.warning(
                         "re-claimed site that was still marked 'claimed' "
                         "because it was last claimed a long time ago "
                         "at %s, and presumably some error stopped it from "
@@ -225,7 +225,7 @@ class RethinkDbFrontier:
         if not job:
             return False
         if job.status.startswith("FINISH"):
-            self.logger.warn("%s is already %s", job, job.status)
+            self.logger.warning("%s is already %s", job, job.status)
             return True
 
         results = self.rr.table("sites").get_all(job_id, index="job_id").run()
@@ -415,7 +415,7 @@ class RethinkDbFrontier:
         assert isinstance(e, brozzler.ReachedLimit)
         if (site.reached_limit
                 and site.reached_limit != e.warcprox_meta["reached-limit"]):
-            self.logger.warn(
+            self.logger.warning(
                     "reached limit %s but site had already reached limit %s",
                     e.warcprox_meta["reached-limit"], self.reached_limit)
         else:
@@ -434,7 +434,7 @@ class RethinkDbFrontier:
                 index="priority_by_site").filter({"hops_from_seed":0}).run()
         pages = list(results)
         if len(pages) > 1:
-            self.logger.warn(
+            self.logger.warning(
                     "more than one seed page for site_id %s ?", site_id)
         if len(pages) < 1:
             return None
diff --git a/brozzler/robots.py b/brozzler/robots.py
index 5b96423..4122093 100644
--- a/brozzler/robots.py
+++ b/brozzler/robots.py
@@ -106,7 +106,7 @@ def is_permitted_by_robots(site, url, proxy=None):
             # reppy has wrapped an exception that we want to bubble up
             raise brozzler.ProxyError(e)
         else:
-            logging.warn(
+            logging.warning(
                     "returning true (permitted) after problem fetching "
                     "robots.txt for %r: %r", url, e)
             return True
diff --git a/brozzler/worker.py b/brozzler/worker.py
index fba83aa..5ce5499 100644
--- a/brozzler/worker.py
+++ b/brozzler/worker.py
@@ -147,13 +147,13 @@ class BrozzlerWorker:
         try:
             with urllib.request.urlopen(request, timeout=600) as response:
                 if response.getcode() != 204:
-                    self.logger.warn(
+                    self.logger.warning(
                             'got "%s %s" response on warcprox '
                             'WARCPROX_WRITE_RECORD request (expected 204)',
                             response.getcode(), response.reason)
                 return request, response
         except urllib.error.HTTPError as e:
-            self.logger.warn(
+            self.logger.warning(
                     'got "%s %s" response on warcprox '
                     'WARCPROX_WRITE_RECORD request (expected 204)',
                     e.getcode(), e.info())
@@ -370,7 +370,7 @@ class BrozzlerWorker:
                 if (page.needs_robots_check and
                         not brozzler.is_permitted_by_robots(
                             site, page.url, self._proxy_for(site))):
-                    logging.warn("page %s is blocked by robots.txt", page.url)
+                    logging.warning("page %s is blocked by robots.txt", page.url)
                     page.blocked_by_robots = True
                     self._frontier.completed_page(site, page)
                 else:
@@ -544,7 +544,7 @@ class BrozzlerWorker:
     def start(self):
         with self._start_stop_lock:
             if self._thread:
-                self.logger.warn(
+                self.logger.warning(
                         'ignoring start request because self._thread is '
                         'not None')
                 return
diff --git a/brozzler/ydl.py b/brozzler/ydl.py
index 57550e5..2388df9 100644
--- a/brozzler/ydl.py
+++ b/brozzler/ydl.py
@@ -48,7 +48,7 @@ _orig_webpage_read_content = youtube_dl.extractor.generic.GenericIE._webpage_rea
 def _webpage_read_content(self, *args, **kwargs):
     content = _orig_webpage_read_content(self, *args, **kwargs)
     if len(content) > 20000000:
-        logging.warn(
+        logging.warning(
                 'bypassing youtube-dl extraction because content is '
                 'too large (%s characters)', len(content))
         return ''
@@ -185,7 +185,7 @@ def _build_youtube_dl(worker, destdir, site):
                     mimetype = magic.from_file(ctx['filename'], mime=True)
                 except ImportError as e:
                     mimetype = 'video/%s' % info_dict['ext']
-                    self.logger.warn(
+                    self.logger.warning(
                             'guessing mimetype %s because %r', mimetype, e)
 
             url = 'youtube-dl:%05d:%s' % (