diff --git a/src/Microsoft.AspNet.WebUtilities/project.json b/src/Microsoft.AspNet.WebUtilities/project.json
index 621e8c5954..88b039b752 100644
--- a/src/Microsoft.AspNet.WebUtilities/project.json
+++ b/src/Microsoft.AspNet.WebUtilities/project.json
@@ -16,6 +16,7 @@
         "dnx451": { },
         "dnxcore50": {
             "dependencies": {
+                "System.Collections": "4.0.11-beta-*",
                 "System.Diagnostics.Debug": "4.0.11-beta-*",
                 "System.IO": "4.0.11-beta-*",
                 "System.IO.FileSystem": "4.0.1-beta-*",