diff --git a/packages/url/package.js b/packages/url/package.js
index 2f015cf221..c5a4759d09 100644
--- a/packages/url/package.js
+++ b/packages/url/package.js
@@ -5,6 +5,7 @@ Package.describe({
 
 Package.onUse(function(api) {
   api.export('URL');
+  api.use('underscore', ['client', 'server']);
   api.addFiles('url_common.js', ['client', 'server']);
   api.addFiles('url_client.js', 'client');
   api.addFiles('url_server.js', 'server');