The impact of education on women’s union formation has long been studied in empirical analyses based on economic and sociological theories. In particular, the literature has shown that the transition to a first union is triggered by the end of education. Mixed evidence has been found on the impact of the level of education. On the other hand, entry into a union usually triggers the end of education. However, the potential endogeneity of educational enrolment and of the timing of union formation has rarely been assessed. In this paper, we use a simultaneous-hazard two-equation model to assess the mutual impact of careers and their potentially common (unobserved) determinants. More specifically, we focus on a yet unstudied institutional setting, namely Central and Eastern European countries. We use micro-data from Fertility and Family Surveys, which refer mainly to the pre-transition period but allow to shed a first light on changes occurring during the transition. Our results for women show that educational enrolment has a key impact on first union formation, but that also the level of education has a substantive impact as expected by Becker’s theory. On the other hand, union formation in almost all countries triggers the end of education. Common unobserved determinants of the two careers have a relatively weak importance.