diff --git a/pywb/manager/manager.py b/pywb/manager/manager.py
index 78d8e3af..4a167cd6 100644
--- a/pywb/manager/manager.py
+++ b/pywb/manager/manager.py
@@ -7,6 +7,7 @@
 import re
 import gzip
 import six
+import pathlib
 
 from distutils.util import strtobool
 from pkg_resources import resource_string, get_distribution
@@ -149,8 +150,11 @@ def add_archives(self, archives, unpack_wacz=False):
 
     def _rename_warc(self, warc_basename):
         dupe_idx = 1
+        ext = ''.join(pathlib.Path(warc_basename).suffixes)
+        pre_ext_name = warc_basename.split(ext)[0]
+
         while True:
-            new_basename = f'{warc_basename}-{dupe_idx}'
+            new_basename = f'{pre_ext_name}-{dupe_idx}{ext}'
             if not os.path.exists(os.path.join(self.archive_dir, new_basename)):
                 break
             dupe_idx += 1
diff --git a/tests/test_manager.py b/tests/test_manager.py
index cc136a8c..6c0abe85 100644
--- a/tests/test_manager.py
+++ b/tests/test_manager.py
@@ -65,6 +65,21 @@ def test_add_valid_archives_unpack_wacz(self, tmp_path):
             assert archive in os.listdir(manager.archive_dir)
             assert archive in index_text
 
+    def test_add_valid_archives_dupe_name(self, tmp_path):
+        manager = self.get_test_collections_manager(tmp_path)
+        warc_filename = 'sample_archive/warcs/example.warc.gz'
+        manager.add_archives(warc_filename)
+        manager.add_archives(warc_filename)
+
+        with open(os.path.join(manager.indexes_dir, manager.DEF_INDEX_FILE), 'r') as f:
+            index_text = f.read()
+
+        expected_archives = ('example.warc.gz', 'example-1.warc.gz')
+
+        for archive in expected_archives:
+            assert archive in os.listdir(manager.archive_dir)
+            assert archive in index_text
+
     def test_add_valid_archives_dont_unpack_wacz(self, tmp_path):
         manager = self.get_test_collections_manager(tmp_path)
         archives = ['sample_archive/warcs/example.arc', 'sample_archive/warcs/example.arc.gz',