On 21 or 22 March 2013, the United Nations Human Rights Council (HRC) will vote on the renewal of the mandate of the Special Rapporteur on the situation of human rights in the Islamic Republic of Iran. In this letter, human rights organisations urge HRC members to support the resolution renewing the mandate of the Special Rapporteur and to strengthen the resolution of the HRC by condemning the patterns of systematic violations committed in Iran and the continued crackdown on dissenting voices and repeated failure to investigate both current and longstanding violations.