Background In 2013 a draft population bill was introduced in the Iranian Parliament. Based on the presumption that fertility in Iran had fallen to a very low level, the bill proposed a wide range of pronatalist policies with the aim of increasing fertility to 2.5 births per woman. The draft law called for restrictions on the employment of women and young single people and inducements for women to marry in their late teens. New estimates of fertility, such as those provided in this paper, cast doubt upon the view that fertility had fallen to a very low level. In May 2014 a statement issued by the Supreme Leader provided guidelines for a more moderate approach to sustaining fertility at around the replacement level. Objective To measure the trend in fertility in Iran, especially from 2000 onwards. Methods Using the 2010 IDHS, the synthetic cohort parity progression ratio method is used to measure the fertility trend in Iran. Synthetic parity progressions are compared with real cohort parity progressions to examine the presence of tempo effects. Comparison is made with age-based measures from surveys, censuses, and the birth registration system. Results This paper demonstrates that fertility in Iran was constant for the decade 2000-2009, at a level of around 1.8-2.0 births per woman. Conclusions Our findings provide evidence supporting a more moderate approach to sustaining fertility in Iran at around the replacement level. Comments The paper demonstrates the advantages of parity-based measurement over age-based measurement when tempo effects may be involved.