Zend_Mail does not check for the correct character set of the mail parts. When instantiating Zend_Mail, a charset for the e-mail itself may be given. It defaults to iso-8859-1. The application has to make sure that all parts added to that mail object have their content encoded in the correct character set. When creating a new mail part, a different charset can be given for each part. Character sets are only applicable for message parts in text format. The following example is how to use Zend_Mail in Japanese. This is one of CJK (aka CJKV ) languages. If you use Chinese, you may use HZ-GB-2312 instead of ISO-2022-JP. setBodyText( myConvert('This is the text of the mail.'), null, Zend_Mime::ENCODING_7BIT ); $mail->setHeaderEncoding(Zend_Mime::ENCODING_BASE64); $mail->setFrom('somebody@example.com', myConvert('Some Sender')); $mail->addTo('somebody_else@example.com', myConvert('Some Recipient')); $mail->setSubject(myConvert('TestSubject')); $mail->send(); ]]>