Several theorists have suggested that genetic risk factors for child conduct problems (CP) should be more influential in low-risk environments, and familial and peer risk factors should be more influential in high-risk environments (Bronfenbrenner & Ceci, 1994; Raine & Venables, 1981). The proposed research was designed to examine how in the context of prolonged neighborhood risk, other risk factors for CP (biological, cognitive, peer, and familial) alter children's developmental trajectories of antisocial behavior. The relative importance of these other CP risk factors will be examined in two samples of ethnically diverse boys. The first includes 310 low-income boys followed longitudinally from infancy to age 12, and the second includes 503 low- and middle-income boys followed from age 7 to young adulthood. Data analysis for this investigation will involve two steps: (1) assigning children to groups based on their joint developmental trajectories of neighborhood risk and CP, and (2) comparing the developmental histories of CP groups within and across neighborhood trajectory types. Multiple measures of neighborhood risk will be employed in this investigation, and the relationship between CP and its risk factors will be assessed using multiple methods and informants. The findings should improve our understanding of how CP develops and identify appropriate targets of intervention in both high- and low-risk neighborhoods. [unreadable] [unreadable]