This study assesses the contribution of migrant childbearing to the overall fertility of a receiving country based on the case of Greece between 2004 and 2012. More specifically, the main aim of the paper is to evaluate the relative contribution of the “fertility behavior” of foreign women and of their share in each age-group to overall fertility in Greece. On the basis of population estimates and of births derived from vital statistics, age-specific fertility rates and total fertility rates (TFRs) are calculated for foreign and Greek women (women born in Greece to Greek parents). The fertility of foreign women is much higher than that of Greek women for all years, although both groups exhibit similar fertility trends. In the period under consideration, the combined effect of foreign fertility and of the share of foreign women in the population increased overall TFR by between 0.06 children per woman (4.4%) and 0.14 children per woman (9.3%). The contribution of foreigners to changes in overall fertility over time is smaller, however. The driving force behind fertility changes is fertility behaviour; population composition effects are minor.