EOT; $dom = new DOMDocument(); $dom->loadXML( $xml, LIBXML_NOBLANKS ); $dom->formatOutput = True; $images = $dom->getElementsByTagName( 'image' ); /* This is the same as your array conversion: */ $sorted = iterator_to_array( $images ); /* This is your sorting routine adapted to DOMDocument: */ usort( $sorted, function( $a, $b ) { return $a->getElementsByTagName('sorted_number')->item(0)->nodeValue - $b->getElementsByTagName('sorted_number')->item(0)->nodeValue; }); /* This is the core loop to “replace” old nodes: */ foreach( $sorted as $node ) $images->item(0)->parentNode->appendChild( $node ); echo $dom->saveXML();