Fertility trends in Iran over recent decades can be plausibly related to a number of causal factors. Population policy shifts were quite marked, and were related to political upheaval and war, which influenced both official policy and popular perceptions of the nation's need for children. A range of developmental factors were also important. The key fertility trends to be explained include the rise to an exceptionally high level in the early 1980s (a TFR of just below 7), and the speed of the subsequent decline to a TFR of about 2.7 in 1996. As well as estimating the proximate determinants of these trends, the paper sets them in their political and developmental context. Iran's fertility trends are then compared with those of Islamic countries of North Africa and West Asia to gain additional insights into possible causal factors. An adequate explanation of fertility change in Iran needs to draw on elements of a number of theories of fertility transition.The key periods of fertility change in Iran over the past three decades have been the onset of a modest decline, mainly in urban areas, in the early 1970s, a resurgence in fertility rates from 1977 to 1984, and the renewed onset of fertility decline since 1988 (Aghajanian and Mehryar 1999; Abbasi-Shavazi 2000b). These changes coincide rather neatly with three political periods: the later stages of the Shah's regime; the Islamic Revolution and the war against Iraq; and a subsequent period of renewed modernization and pragmatism. There appears, then, to be a relationship between the dramatic political events and fertility trends. The obvious linkage is the shifts in population policy that took place over the period: antinatalism and a governmentsponsored family planning program in the later stages of the Shah's regime; denunciation of family planning and encouragement of early marriage in the post-Revolutionary period; and a pragmatic return to antinatalism in the post-1988 period.Fertility has declined dramatically since the adoption of a new population policy in 1988. This rapid decline was greeted with incredulity for some time by many overseas observers. The reason was that much of the world was unaware that in the period following the Islamic Revolution, social change consisted not only of a