Mongolia has never been a member of the USSR, but the collapse of the Soviet Union deeply affected this country. While a growing body of literature documents the consequences of this collapse on fertility and family formation behaviour for the former socialist countries in Central and Eastern Europe, the Baltic countries, Russia and Ukraine, and more recently, countries in Central Asia, Mongolia received only limited attention. This paper aims to fill this gap. As a consequence of the transition to democracy and a market economy, Mongolia experienced an impressive fertility reduction; total fertility fell from 4.6 children per woman to 2.5 between 1989 and 1993. Through the application of the synthetic parity progression ratios method to the 1998 Reproductive Health Survey data, this study analyses the reproductive responses of Mongolian couples in a context of deep social and economic changes. Paralleling other ex-socialist countries, it is shown that the transition affected the reproductive behaviour in Mongolia. Marriage declined discernibly for Mongolian women, but was shortly followed by a first birth. The changes took place at parities higher than two. These results suggest that people adjust their reproductive behaviour according to strongly-rooted cultural values that balance the standard economic motivations.