diff --git a/lib/yard/registry.rb b/lib/yard/registry.rb
index <HASH>..<HASH> 100644
--- a/lib/yard/registry.rb
+++ b/lib/yard/registry.rb
@@ -20,7 +20,7 @@ module YARD
       end
     end
 
-    def at(path) namespace[path] end
+    def at(path) path.to_s.empty? ? root : namespace[path] end
     def root; namespace[:root] end
     def delete(object) namespace.delete(object.path) end
     def clear; initialize end
If #at() receives empty string, it belongs to root