Background: Problems related to gangs have been noted in large cities and in many schools across the United States. This study examined the patterns of alcohol, drug use, and related exposures among male and female high school students who were gang members. Methods: Analyses were based on the Youth Violence Survey, conducted in 2004, and administered to over 80% of eligible public school students in grades 7, 9, 11, and 12 (N = 4131) in a high-risk, urban school district. The self-administered survey, completed during a class period, included measures of alcohol and drug use and related exposures. Tests of associations were determined using chi-square tests and logistic regression analyses. Results: In this study, 8.8% of students reported gang membership. Students who initiated alcohol use prior to age 13 (OR = 4.90; 95% CI: 3.65-6.58), who drank alcohol 3 or more times per week (OR = 9.57; 95% CI: 6.09-15.03) and who used drugs 3 or more times per week (OR = 6.51; 95% CI: 4.59-9.25) were more likely to report gang membership than students who did not report alcohol or drug use. Boys were more likely than girls to report alcohol-related fighting and drug selling. Discussion: Gang members were significantly more likely than non-gang members to have initiated alcohol early, to have reported a high prevalence of alcohol use, to have engaged in alcohol-related physical fighting, peer drinking, drug use, drug selling, peer drug selling, and having seen drug deals in their neighborhood. Schools may serve as a critically important source for intervention and prevention efforts for gang members, especially those in 7th grade, who still attend school. (Contains 3 tables.)