Objective: To examine the effect of prenatal and infancy nurse home visitation on the life course development of 19-year-old youths whose mothers participated in the program. Design: Randomized trial. Setting: Semirural community in New York. Participants: Three hundred ten youths from the 400 families enrolled in the Elmira Nurse-Family Partnership program. Intervention: Families received a mean of 9 home visits (range, 0-16) during pregnancy and 23 (range, 0-59) from birth through the child's second birthday. Main Outcome Measures: Youth self-reports of educational achievement, reproductive behaviors, welfare use, and criminal involvement. Results: Relative to the comparison group, girls in the pregnancy and infancy nurse-visited group were less likely to have been arrested (10% vs 30%; relative risk [RR], 0.33; 95% confidence interval [CI], 0.13-0.82) and convicted (4% vs 20%; 0.20; 0.05-0.85) and had fewer lifetime arrests (mean: 0.10 vs 0.54; incidence RR [IRR], 0.18;95% CI, 0.06-0.54) and convictions (0.04 vs 0.37; 0.11; 0.02-0.51). Nurse-visited girls born to unmarried and low-income mothers had fewer children (11% vs 30%; RR, 0.35; 95% CI, 0.12-1.02) and less Medicaid use (18% vs 45%; 0.40; 0.18-0.87) than their comparison group counterparts. Conclusions: Prenatal and infancy home visitation reduced the proportion of girls entering the criminal justice system. For girls born to high-risk mothers, there were additional positive program effects consistent with results from earlier phases of this trial. There were few program effects for boys. (author abstract)