Tehran University of Medical Sciences Iranian Journal of Psychiatry 1735-4587 9 2 2014 06 15 115 7 Yaghoob Vakili North Khorasan University of Medical Sciences, Bojnord, Iran Banafshe Gharraee Department of Psychiatry, Tehran Institute of Psychiatry, Iran University of Medical Sciences, Tehran, Iran 2015 10 14 Objective: The aim of this study was to evaluate the effectiveness of acceptance and commitment therapy (ACT) in treating obsessive compulsive disorder (OCD). Method: In a single-subject experiment trial, the treatment process was carried out on a 39-year old male subject. The patient satisfied the DSM-IV-TR criteria for OCD and was assessed for pre-duration and post treatment. The scales used in this study included: The Yale-Brown Obsessive Compulsive Scale(Y-BOCS), Beck Depression Inventory-II-second edition (BDI-II), and Beck Anxiety Inventory (BAI). In addition, all scales were again completed by the subject at 1-month, 3-months, and 6-months follow-ups. Results: The treatment led to reductions in symptoms of OCD, depression and anxiety. Gains were maintained at follow-ups. Conclusion: The treatment approach appears to be effective in the treatment of OCD. https://ijps.tums.ac.ir/index.php/ijps/article/view/104 https://ijps.tums.ac.ir/index.php/ijps/article/download/104/100