This paper examines the impact of in utero exposure to the Asian influenza pandemic of 1957 upon childhood development. Outcome data are provided by the National Child Development Study (NCDS), a panel study where all members were potentially exposed in the womb. Epidemic effects are identified using geographic variation in a surrogate measure of the epidemic. Results point to multiple channels linking fetal health shocks to childhood outcomes: physical development is impeded, but only when mothers had certain health characteristics; by contrast, the negative effects on cognitive development appear general across the cohort. (Contains 6 tables and 22 footnotes.)