Prospective longitudinal data from 585 families were used to examine parents' reports of child physical abuse in the first 5 years of life as a predictor of substance use at ages 12, 16, and 24. Path analyses revealed that physical abuse in the first 5 years of life predicted subsequent substance use for females but not males. We found a direct effect of early physical abuse on girls'substance use at age 12 and indirect effects on substance use at age 16 and age 24 through substance use at age 12. For boys, age 12 substance use predicted age 16 substance use, and age 16 substance use predicted age 24 substance use, but physical abuse in the first 5 years of life was unrelated to subsequent substance use. These findings suggest that for females, a mechanism of influence of early physical abuse on substance use into early adulthood appears to be through precocious initiation of substance use in early adolescence.