This paper analyses how maternal labor supply relates to the availability of childcare services in Flanders, a region that has a fairly abundant service provision, but does not offer a service guarantee as in several Nordic countries. Variation in price/quantity bundles that stems from the interplay of three types of childcare services are used to identify mothers' labor supply responses. The estimates indicate that policy measures which increase the availability may exhibit large labor supply effects. Moreover, budgetary simulations suggest the expansion of subsidised care services to be beneficial to the exchequer. (author abstract)