Giorgio Bertolotti,1 Paolo Michielin,2 Giulio Vidotto,2 Ezio Sanavio,2 Gioia Bottesi,2 Ornella Bettinardi,3 Anna Maria Zotti4 1Psychology Unit, Salvatore Maugeri Foundation, IRCCS, Scientific Institute, Tradate, VA, 2Department of General Psychology, Padua University, Padova, 3Department of Mental Health and Addictive Behavior, AUSL Piacenza, Piacenza, 4Salvatore Maugeri Foundation, IRCCS, Scientific Institute, Veruno, NO, Italy Background: Cognitive behavioral assessment for outcome evaluation was developed to evaluate psychological treatment interventions, especially for counseling and psychotherapy. It is made up of 80 items and five scales: anxiety, well-being, perception of positive change, depression, and psychological distress. The aim of the study was to present the metric qualities and to show validity and reliability of the five constructs of the questionnaire both in nonclinical and clinical subjects. Methods: Four steps were completed to assess reliability and factor structure: criterion-related and concurrent validity, responsiveness, and convergent–divergent validity. A nonclinical group of 269 subjects was enrolled, as was a clinical group comprising 168 adults undergoing psychotherapy and psychological counseling provided by the Italian public health service. Results: Cronbach’s alphas were between 0.80 and 0.91 for the clinical sample and between 0.74 and 0.91 in the nonclinical one. We observed an excellent structural validity for the five interrelated dimensions. The clinical group showed higher scores in the anxiety, depression, and psychological distress scales, as well as lower scores in well-being and perception of positive change scales than those observed in the nonclinical group. Responsiveness was large for the anxiety, well-being, and depression scales; the psychological distress and perception of positive change scales showed a moderate effect. Conclusion: The questionnaire showed excellent psychometric properties, thus demonstrating that the questionnaire is a good evaluative instrument, with which to assess pre- and post-treatment outcomes. Keywords: outcome evaluation, well-being, treatment effects, patient perception, anxiety, depression, questionnaire