The questionnaire contained 45 forced-choice questions and was returned by 1,801 of the more than 2,500 potential respondents, for a response rate of more than 70 percent. Results revealed that the youths had a median age of 16 years and 87.8 percent were male. A total of 18.9 percent were Hispanic, 27.1 percent white, 46.1 percent black, and 7.9 percent other. In addition, 46.1 percent of the youths reported having joined a gang at some time, compared to an estimated 3 percent of the adult prison population. Moreover, gang members drank alcohol earlier in life than the other youths; drank more often and more heavily; used marijuana earlier and more heavily; and used cocaine, crack, and other drugs more heavily. They were also more likely to report having willingly had sexual relations at age 12 or earlier and were less likely to use any method to prevent pregnancy or sexually transmitted diseases. Findings indicated the need for increased resources devoted to reducing the health risk behavior of juveniles and especially juveniles affiliated with gangs. Tables and 10 references