diff --git a/xsl/xmlsitemap.xsl b/xsl/xmlsitemap.xsl
index f7ff8ec..671c64b 100644
--- a/xsl/xmlsitemap.xsl
+++ b/xsl/xmlsitemap.xsl
@@ -27,7 +27,7 @@
     xmlns:html="http://www.w3.org/TR/REC-html40"
     xmlns:sitemap="http://www.sitemaps.org/schemas/sitemap/0.9"
     xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
-  <xsl:output method="html" version="1.0" encoding="utf-8" indent="yes"/>
+  <xsl:output method="html" doctype-public="-//W3C//DTD XHTML 1.0 Strict//EN" doctype-system="http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd" version="1.0" encoding="utf-8" indent="yes"/>
   <!-- Root template -->
   <xsl:template match="/">
     <html>