Like many former Soviet and Eastern European countries, the Dolgan and Nganasan community of Ust’-Avam, Siberia, experienced a rapid decline in fertility following the collapse of the Soviet Union in 1991. The collapse of the Soviet planned economy brought abrupt and catastrophic economic changes to the community, including mass layoffs, rapidly increasing costs for non-local goods, transportation, and spare parts, and a reorientation to a mixed-cash subsistence economy. Fertility declined abruptly in response to this economic upheaval: over the ten-year span from 1993–2003, the implied Total Fertility Rate declined from about 5 to just over 1 child per woman (compared to a decline of about 1 child per woman in post-Soviet countries). By comparing age at first birth and inter-birth intervals over this period, we look more closely at the proximate mechanisms driving this decline in fertility in this population and relate our findings to responses to risk and uncertainty in this rapidly changing local socioeconomic context.