diff --git a/pygtk-imap-chk.py b/pygtk-imap-chk.py
index 0c832ba..b5c6012 100755
--- a/pygtk-imap-chk.py
+++ b/pygtk-imap-chk.py
@@ -41,6 +41,14 @@ def main(argv):
     config_fname = argv[1]
 
     conf = get_config(config_fname)
+    if not ('server' in conf
+            and 'port' in conf
+            and 'user' in conf
+            and 'password' in conf):
+        sys.stderr.write(
+                'Must specify server, port, user, and password'
+                ' in configuration file\n')
+        return 1
 
     window = Window(conf)
     window.run()