Young children are thought to be vulnerable to separation from their primary caregiver. This raises concern about whether early childcare enrollment may harm child development. We use childcare assignment lotteries to estimate the effect of enrollment at age 1–2 on cognitive development in Norway. Estimates show significant gains in language and mathematics at age 6–7 and a substantial drop in scores below publicly set thresholds for low performance. Across subsamples, we find a pattern of stronger effects on underperforming groups. We find little support for childcare quality or family income as drivers of our results.