Background: Few studies have investigated the role of the intermediate variables of fertility at the micro-level in Italy, and, in particular, little is known about the influence of socioeconomic factors. This is the reason that the mechanisms through which women arrived at the control of their own fertility are still largely unexplored.

Objective: We wish to analyze the role of education and socioeconomic determinants on the process of fertility transition in four Italian populations, by focusing on the birth cohorts born between the end of the 19th century and the first decade of the 20th century.

Methods: Data comes from the census returns of 1961, which include a Fertility Survey aimed at gathering information on the reproductive history of ever-married women. A negative binomial regression was then carried out to check the influence of some socioeconomic determinants on the completed family size of such women.

Results: Among socioeconomic factors, women's education proves to be more important than family economic status in shaping fertility levels, with highly educated women showing a smaller completed family size than illiterate ones. In particular, fertility differentials by educational attainment appear to be wider at the beginning of the transition.

Conclusions: The use of micro-level data has allowed us to shed some light on the importance of women's education, especially in the first stages of fertility transition, resulting in one of the possible explanations for ist different onsets in the various regions of Italy.