diff --git a/electrum b/electrum
index 30f60eac..1bb630fd 100755
--- a/electrum
+++ b/electrum
@@ -89,7 +89,7 @@ if __name__ == '__main__':
     parser = arg_parser()
     options, args = parser.parse_args()
     if options.portable and options.wallet_path is None:
-        options.wallet_path = os.path.dirname(os.path.realpath(__file__)) + '/electrum.dat'
+        options.wallet_path = os.path.join(os.path.dirname(os.path.realpath(__file__)), 'electrum.dat')
     set_verbosity(options.verbose)
 
     # config is an object passed to the various constructors (wallet, interface, gui)