100 Spanish-speaking substance using individuals seeking treatment at the Hispanic Clinic of the Connecticut Mental Health Center will be randomized to (1) standard outpatient counseling at the Hispanic Clinic (typically consisting of weekly group counseling), OR (2) CBT4CBT plus standard outpatient counseling. Treatments will be delivered over an 8-week period with a six-month follow-up after termination of the study treatments. The primary outcome measures will be reduction in substance use (frequency of substance use by time, confirmed by urine toxicology screens and breathalyzers). Secondary outcomes will include treatment utilization and cost, several measures intended to detect whether web-based CBT4CBT retains key characteristics of traditional clinician-administered CBT (e.g., acquisition of coping skills, use of change strategies), participant characteristics which will be evaluated as potential moderators of outcome, as well as participant satisfaction and treatment credibility.