We report the results of a parallel-process, latent growth model analysis examining the relationships between cocaine use and delinquent behavior among youths. The study examined a sample of 278 justice-involved juveniles completing at least one of three follow-up interviews as part of a National Institute on Drug Abuse-funded study. The results of our analysis of the cocaine use and delinquency parallel-process model highlighted that these phenomena are mutually related experiences over time. Particularly noteworthy is the significant, positive relationship between cocaine trend and delinquency trend: as the rate of change in cocaine use increases, a corresponding change occurs in engaging in delinquent behavior. Implications for policy and intervention service needs are discussed. (Contains 6 tables, 1 figure, and 1 footnote.)