Objectives: To examine the stability of comorbid psychiatric diagnoses among a sample of 50 adolescents in cognitive-behaviorally-based treatment for alcohol and other substance use disorders (AOSUD). Methods: A standardized psychiatric interview was administered at baseline and 12 month later to obtain current comorbid psychiatric disorders. Chi square and Wilconxon sign tests coefficients were used to examine changes in threshold status by type of disorder. Pearson's coefficients were used to identify correlates with improvements in threshold status, include the need for alcohol treatment and alcohol consumption at follow-up. Results: Diagnostic status changes considerably over time. Prevalence rates for comorbid disorders overall declined. Only declines in mood and externalizing disorders achieved statistical significance. Improvements were positively correlated with mental health service utilization and negatively correlated with the need for alcohol treatment and consumption at 12 months. Conclusions: Further investigation on the stability and change in diagnostic status of AOSUD youths is warranted. (Contains 3 tables.)