This study investigates some of the mechanisms, which lead to social inequalities in the usage of early childhood education and care (ECEC) by focusing on a recent period of public childcare expansion in Germany. Based on sociological rational educational decision models, we model the decision to use ECEC as a rational cost-benefit investment strategy, which simultaneously affects the human capital of mothers and children. We test our assumptions with data from the new-born cohort of the German National Educational Panel Study (NEPS-SC1), estimating event history models. Results indicate that cost-benefit calculations are indeed relevant for the timing of ECEC take-up, but do not explain social differences. Mothers who perceive ECEC take-up as an investment into child development and as an opportunity to maintain their own occupational status take up ECEC earlier. This
association is particularly pronounced for highly educated mothers. Moreover, differences for East and West Germany highlight the importance of the cultural context for cost-benefit considerations.