The epidemiology model holds that disease does not develop randomly within the human population, but rather is the result of exposure to multiple risk factors within the individual's environment. The population for the current study consisted of self-reporting gang and nongang members who were incarcerated in North Carolina institutions for misdemeanor charges, felony charges, or a combination of such charges. The population was composed of all such inmates regardless of their admission date, crime, length of sentence, or release date. The original sample numbered 1,512 participants, of which 396 were gang members and 1,116 were nongang members. To ensure that the analysis was not skewed by the large number of nongang members, a comparable group of 390 nongang members was selected and used throughout the study for data analysis. The risk factors for gang membership were in five categories: family, school, community, individual, and peers. All of the categories except school were found to be statistically significant for gang membership. This was due to minimal distinctive responses between gang and nongang members on items in the "school" category. The categories of "family" and "individual" had the highest statistical significance and thus the highest level of predictability for gang membership. Individuals who had been bullied, had engaged in delinquent behavior, and had faced social and economic barriers were at increased risk for gang membership. The findings did not reveal a single individualized risk factor that was indicative of gang membership for all age groups; thus, age did not apparently affect the individualized risk factor and the decision to become a gang member. Delinquent behavior was statistically significant for the age group 20-25 at the level of .0015. The odds ratio for gang membership was 3.7275 for those 20-25 who had bullied someone. The best indicator for gang membership for the 20-25 age group was the categorical risk factor "individual" and individualized risk factor "engaged in delinquent behavior." Social and economic barriers were significant risk factors for gang members for the age group 26-34, suggesting that even older individuals might consider becoming gang members if their social and economic opportunities are limited. These findings therefore show that the risk factors for gang membership are associated with the age of the individual, suggesting insight into possible prevention and intervention strategies. Suggestions are offered for future research. 3 tables and 19 references