The study, based on interviews with 415 youths on probation, compares gang- and non-gang-affiliated adolescents across individual, family, interpersonal and environmental assessment domains. Lower perceived prosocial opportunities, more gang activity in their neighborhoods, greater personal alcohol and drug use, and more extensive antisocial peer networks distinguish gang from non-gang members. Preliminary findings indicate that gang-related youth may be at greater risk for serious offending than non-gang-involved delinquents. However, gang membership is an unstable activity among juvenile offenders and the absence of longitudinal data ruled out assessment over time of changes in gang status. This study was conducted in Utah, a State in which gangs are a relatively recent phenomenon. Results may not be generalizable to probationers residing in areas with established traditions of gang activity. The article recommends additional research into the etiology of gang membership in order to inform prevention and treatment efforts targeting delinquent youth at high risk for gang involvement. Tables, references