This paper reviews predictors of treatment response in open and controlled trials of cognitive-behavioral therapy for obsessive-compulsive disorder (OCD). We focus on demographic characteristics, aspects of OCD symptoms, comorbidity, family factors, cognitive influences, and treatment-specific characteristics as predictor variables. Although inconsistent findings characterize much of the literature, several relatively consistent and salient predictors have emerged, including symptom severity, symptom subtype, severe depression, the presence of comorbid personality disorders, family dysfunction, and the therapeutic alliance. Implications of findings and recommendations for future research are discussed. (c) 2007 Elsevier Ltd. All rights reserved.