By using the Demographic and Health Survey (DHS) data for 42 developing countries this paper studies the impact of fertility on mothers’ employment. In order to solve the problem of omitted variable bias multiple births are used as source of variation in family size. Similarly to previous evidence for developed countries, the findings reveal that family size has a negative impact on female employment. Nevertheless, two types of heterogeneity are exposed. First, the
size and sign of the impact depends on the birth at which we study the increase in family size; specifically, a negative impact of fertility is observed at the time of the first birth or in a third and higher births; nevertheless, for some samples (and definitions of mother’s employment) a shift in a second birth might have a ositive impact on employment. Second, the types of jobs affected by a change of fertility differ depending on at which margin the shift in fertility takes place. Thus, while for a first birth, more informal jobs, such as unpaid jobs, or jobs that are harder to combine with childbearing (working away from home or seasonal jobs) are the ones impacted by an increase in family size; at higher parities, all type of jobs are affected by the shift in fertility.