The Yale Adherence and Competence Scale (YACS) is a general system for rating therapist adherence and competence in delivering behavioral treatments for substance use disorders. The system includes three scales measuring 'general' aspects of drug abuse treatment (assessment, general support, goals of treatment), as well as three scales measuring critical elements of three treatments that are frequently implemented as control or comparison treatments in clinical research in the addictions (clinical management (CM), twelve step facilitation (TSF), and cognitive behavioral therapy (CBT)). Validation of the YACS using data from a randomized clinical trial indicated that the scales have excellent reliability, factor structure, concurrent and discriminant validity. Correlations between adherence and competence scores within scales were in the moderate range, indicating independence (and thus nonredundancy) of these dimensions. Strategies for using the YACS in both psychotherapy and pharmacotherapy research in the addictions are described.