Exploiting the exogenous variation in user fees caused by a Swedish childcare reform, we are able to identify the causal effect of childcare costs on fertility in a context in which childcare enrollment is almost universal, user fees are low, and labor force participation of mothers is very high. Anticipation of a reduction in childcare costs increased the number of first and higher-order births, but only seemed to affect the timing of second births. For families with many children we also find a marginally significant negative income effect on fertility.