Few studies have explored the longitudinal relationship between commercial sexual exploitation (CSE) and the use of specific types of substances by male youth. To gain a more comprehensive understanding of the links between CSE and substance use in male youth, the current study explored this connection using longitudinal data collected from a sample of 98 male serious youthful offenders with reported incidents of CSE/prostitution. Study findings indicated that alcohol use and marijuana use, rather than the use of more serious types of drugs, were concurrently linked to involvement in CSE/prostitution. Using parallel-process latent growth modeling, associations between alcohol and marijuana use were observed, with alcohol use significantly impacting chronic and persistent CSE/prostitution. The findings highlight the need for CSE intervention programs designed for male youth to include screening and treatment for marijuana – and especially alcohol – use.