diff --git a/archreposrv b/archreposrv
index 5c29883..2a350c9 100755
--- a/archreposrv
+++ b/archreposrv
@@ -12,16 +12,25 @@ enable_pretty_logging(logging.DEBUG)
 
 from repomon import repomon
 
-def main(conffile):
-  config = configparser.ConfigParser(default_section='multi')
-  config.read(conffile)
-
+def check_and_get_repos(config):
   repos = config['multi'].get('repos', 'repository')
   for field in ('name', 'path'):
     if config['multi'].get(field, None) is not None:
-      raise ValueError('The config %r cannot have default value.' % field)
+      raise ValueError('config %r cannot have default value.' % field)
+
+  repos = {repo.strip() for repo in repos.split(',')}
+  for field in ('name', 'path'):
+    vals = [config[repo].get(field) for repo in repos]
+    if len(vals) != len(set(vals)):
+      raise ValueError('duplicate %s in different repositories.' % field)
+
+  return repos
+
+def main(conffile):
+  config = configparser.ConfigParser(default_section='multi')
+  config.read(conffile)
+  repos = check_and_get_repos(config)
 
-  repos = [repo.strip() for repo in repos.split(',')]
   notifiers = [repomon(config[repo]) for repo in repos]
 
   ioloop = IOLoop.instance()