Immigration to Sweden is dominated by women and men of childbearing age, and many arrive with children. The labour-market integration of newly arrived mothers is of concern, and well directed social policy is crucial. Parental leave is based on residence, and until recently it was granted to all parents of foreign-born children of preschool age. This study uses population and social insurance registers to investigate whether newly arrived immigrant mothers use parental leave upon arrival, and whether use is an obstacle to future labour-market activity. Our results indicate that the majority of the newly arrived mothers do not take any parental leave, but also that there are great differences in uptake in relation to country of birth and reason for residence permit. However, there seem to be only marginal associations between parental leave use and subsequent labour-market attachment. Nevertheless, moderate use is associated with labour-market activity rather than being an obstacle to it. Our results contribute to the debate on the unintended effects of social policy on the integration of immigrants.