The present study evaluates adolescent gang involvement using cross-sectional survey data from 1,475 adolescents living in a disadvantaged Comuna in Medellin, Colombia. Specifically, we examine the prevalence of former and current gang membership, affiliation with gang members, and lives untouched by any gang association. Once these groups are established, we identify variation in membership on the basis of demographic and theoretical variables, and determine whether such variation can be described by using the selection, facilitation, and enhancement models developed by Thornberry et al. While our results, consistent with many prior findings using North American samples, support the "selection" model for most theoretical variables and "enhancement" for behavioral outcomes, our strongest contribution is our study's ability to demonstrate the temporal impact of gang involvement.