There are two methods that save changes to PDF documents: the Zend_Pdf::save() and Zend_Pdf::render() methods. Zend_Pdf::save($filename, $updateOnly = false) saves the PDF document to a file. If $updateOnly is true, then only the new PDF file segment is appended to a file. Otherwise, the file is overwritten. Zend_Pdf::render($newSegmentOnly = false) returns the PDF document as a string. If $newSegmentOnly is true, then only the new PDF file segment is returned. save($fileName, true); // Save document as a new file $pdf->save($newFileName); // Return the PDF document as a string $pdfString = $pdf->render(); ... ]]>