diff --git a/xslt/epub2i5.xsl b/xslt/epub2i5.xsl
index 2c59831..734e644 100644
--- a/xslt/epub2i5.xsl
+++ b/xslt/epub2i5.xsl
@@ -333,6 +333,9 @@
                                             <idno type="{$type}"><xsl:value-of select="replace(., '(([0-9]|-)+X?).*', '$1')"/></idno>
                                         </xsl:if>
                                     </xsl:when>
+                                    <xsl:when test="$type='URN'">
+                                        <idno rend="URN" type="URN"><xsl:value-of select="."/></idno>
+                                    </xsl:when>
                                     <xsl:otherwise><idno type="{$type}"><xsl:value-of select="."/></idno></xsl:otherwise>
                                 </xsl:choose>
                             </xsl:for-each>