Background: This study aimed to evaluate the effectiveness of an acceptance and commitment-based therapy (ACT) for three patients with treatment-resistant obsessive compulsive disorder (OCD).

Materials and Methods: A single case-design was carried out on three patients with treatment-resistant OCD. Data were collected using a Yale Brown obsessive compulsive scale, Beck depression inventory-II, Beck anxiety inventory and a processing measure.

Results: Results showed a significant alleviation in obsessive symptoms, scores of anxiety and depression, believability and distress of obsessions and need to response to them in post-test among three patients and the alleviation continued for 1-month follow-up.

Conclusion: Results of this study show that the acceptance and commitment-based therapy can be an effective treatment for patients with treatment-resistant OCD.