With 3.1 children per woman in 2015, Mongolia appears today as an exception in East Asia where fertility rates are far below the replacement level. Moreover, from its historical nadir of 1.95 children per women in 2005, fertility is on the rise. This chapter first presents recent fertility development in Mongolia. Second, it aims to present fertility preferences and trends. Reproductive Health Surveys and Social Indicator Sampling Surveys are both used for the same practice of collecting indicators on fertility preference. It is very interesting to see that the ideal number of children has been stable at around three to four children for the last 20 years in Mongolia. There is an absence of any sex preference in favour of boys. Lastly, the policy implications are highlighted, as there is a need to discuss policies with realistic goals if the country still wants to maintain or grow its population in the future.