diff --git a/templates.go b/templates.go
index 34ac3bd..62398c1 100644
--- a/templates.go
+++ b/templates.go
@@ -9,7 +9,7 @@ const atom_xml = `<?xml version="1.0" encoding="utf-8"?>
 <title>{{ .Title }}</title>
 <link href="{{ .URL }}"/>
 <link rel="self" href="{{ .URL }}{{ .Path }}"/>
-<updated>{{ .Updated }}</updated>
+<updated>{{ .Updated.Format "2006-01-02T15:04:05Z07:00" }}</updated>
 <id>{{ .URL }}{{ .Path }}</id>
 {{- $url := .URL -}}
 {{- range .Entries }}