We report on the long-term effects of in utero exposure to air lead on adult socio-eco-nomic outcomes, including earnings, disabilities, employment, public assistance, and education. Using US administrative data, we match individuals in the 2000 Decennial Census and 2001-2014 American Community Surveys to the county of their birth and birth date, and then to aver-age lead concentrations in that county during the individual's 9 months in utero. We find a 0.5 μg/m3 decrease in air lead, representing the average 1975-85 change, is associated with an in-crease in earnings of 3.9%. Long-term effects for girls seem to be on the extensive margin of working at all, whereas for boys it appears to fall more on the intensive margin of hours worked.