This article explores marital fertility on the Aegean island of Paros based on family-reconstitution data from one main town and one village on the island, namely Naoussa and Kostos. By probing the reproductive behaviour of couples who married between 1894 and 1953 it was found that fertility was still ‘natural’ on the island at the beginning of the twentieth century, while a substantial fertility decline made itself visible only in the late 1920s and early 1930s. The way the population switched from natural to controlled fertility is also explored, as well as the contribution of different socio-economic groups to fertility transition. In the end, an effort is made to place the examined population in a wider European and national context.