diff --git a/drive-download.py b/drive-download.py
index e1c2b8f..036a877 100644
--- a/drive-download.py
+++ b/drive-download.py
@@ -6,10 +6,17 @@ if sys.version_info < (3, 3):
     sys.exit(1)
 
 import os
+import pickle
 import shlex
 from pydrive.auth import GoogleAuth
 from pydrive.drive import GoogleDrive
 
+try:
+    with open(os.path.expanduser('~/.local/share/drive-download/seen.pickle'), 'rb') as f:
+        seen = pickle.load(f)
+except FileNotFoundError:
+    seen = set()
+
 gauth = GoogleAuth(settings_file=os.path.expanduser('~/.config/drive-download/settings.yaml'))
 gauth.CommandLineAuth()
 
@@ -19,9 +26,15 @@ file_list = drive.ListFile({'q': "'{}' in parents and trashed=false".format(FOLD
 for file1 in file_list:
     if file1['mimeType'] == 'application/vnd.google-apps.folder':
         continue
+    if file1['id'] in seen:
+        continue
+
     local_filename = file1['title']
     print(shlex.quote(local_filename))
     if not os.path.exists(local_filename):
         file1.GetContentFile(local_filename)
+        seen.add(file1['id'])
+        with open(os.path.expanduser('~/.local/share/drive-download/seen.pickle'), 'wb') as f:
+            pickle.dump(seen, f)
     else:
         raise RuntimeError("{} exists".format(shlex.quote(local_filename)))