diff --git a/lib/spack/docs/packages_yaml.rst b/lib/spack/docs/packages_yaml.rst
index e08f51e612..c46665daab 100644
--- a/lib/spack/docs/packages_yaml.rst
+++ b/lib/spack/docs/packages_yaml.rst
@@ -546,10 +546,11 @@ You can assign class-level attributes in the configuration:
 
   packages:
     mpileaks:
-      # Override existing attributes
-      url: http://www.somewhereelse.com/mpileaks-1.0.tar.gz
-      # ... or add new ones
-      x: 1
+      package_attributes:
+        # Override existing attributes
+        url: http://www.somewhereelse.com/mpileaks-1.0.tar.gz
+        # ... or add new ones
+        x: 1
 
 Attributes set this way will be accessible to any method executed
 in the package.py file (e.g. the ``install()`` method). Values for these