The increase in the annual homicide rate for 15- to 19-year-old males during 1985-1991 was a dramatic change from the pattern during 1963-1984. This may be the result of the recruitment of juveniles into drug markets, the use of guns in those markets, and the consequent diffusion of guns to other young persons in the community, resulting, in turn, in more frequent use of the guns for settling disputes. Factors underlying increased gun use may include poverty, inadequate educational and economic opportunities, social and family instability, and frequent personal exposure to violence as an acceptable or preferred method of resolving disagreements. Intervention strategies to prevent youth violence include: (1) strengthening the science base for prevention efforts; (2) establishing primary-prevention programs; (3) targeting youths of all ages; (4) involving adults; (5) presenting messages in multiple settings; and (6) addressing societal and personal factors. There is a section on adolescent homicides in Fulton County, GA, 1988-1992. Tables, references