Background: Irritable bowel syndrome (IBS) is a functional disorder of the lower gastrointestinal (GI) tract caused by stress and is also is associated with anxiety and depression which may benefit from a treatment such as mindfulness.

Objectives: to determine the effectiveness of the mindfulness in decreasing the anxiety and depression in the patients suffering from IBS.

Methods: The research design was based on single-subject. Three IBS patients diagnosed by Rome-II criteria participated in this treatment project in Tabriz in 2015 voluntarily and with their personal consent. Eight sessions of Mindfulness-Based Stress Reduction (MBSR) were held for them individually. Beck Anxiety Inventory (BAI) and Beck Depression Inventory-II (BDI-II) were used before starting the treatment and at the end of the second, fourth, sixth and eighth sessions regarding to their intensity of anxiety and depression.

Results: The anxiety and the depression scores of each subject were decreased in post-test comparing with pre-test. The percentage of the three patients' remission regarding to the anxiety by BAI were 86.67, 56.52 and 70.59 percent and the remission percentage average was 65.25. The percentage of remission regarding to the depression by BDI-II were 35.29, 65.12, 95.24 respectively, and the average percentage of the remission was 57.14.

Conclusion: Based on the research findings, the treatment education and MBSR had the positive impact on decreasing the anxiety and e depression of the patients suffering from IBS.