Drug dealers may be at increased risk for drug use. However, there is a dearth of research focused on how these relationships develop across time. Group-based trajectory modeling (GBTM) was used to assess heterogeneity in the development of drug dealing behavior. Line graphs modeling the average frequency of use of drugs across time based on trajectory membership described drug use patterns. T-tests were used to test for significant differences between drug use patterns. Results indicated that a four-group model of drug dealing best fit the data. Changes in each type of drug use corresponded strongly with changes in drug dealing behaviors.