Low labor force participation among mothers in North Africa and the Middle East is often attributed to cultural factors independent of economic considerations. There is little evidence, however, to support or refute this view. In September 1999, the Israeli government introduced free public preschool for children aged 3 and 4. I use this policy change to estimate the effects of a reduction in child care costs on preschool enrollment, and Arab mothers' labor supply and fertility. I find that as a result of the intervention, preschool enrollment and mothers' labor supply both increased sharply. The increase in labor supply occurred mainly among more educated mothers. In spite of increasing labor force participation, the fertility of these mothers appears to have been unchanged in the short-run. There is no evidence of an effect on mothers in affected towns who did not have children of preschool age. (author abstract)