diff --git a/pisi-spec.rng b/pisi-spec.rng
index 6b078ed8..9c602a0c 100644
--- a/pisi-spec.rng
+++ b/pisi-spec.rng
@@ -235,6 +235,7 @@
                     <value>tarlzma</value>
                     <value>tar</value>
                     <value>zip</value>
+                    <value>gzip</value>
                     <value>binary</value>
                 </choice>
             </attribute>