Background: Various psychological interventions were considered as part of the treatments of irritable bowel syndrome. However, the effectiveness of coping strategies in improving symptoms of this disease remains unclear. The objective of this study was to assess the effects of coping strategies training in treatment of irritable bowel syndrome (IBS). Methods: In this randomized, placebo-controlled trial 46 consecutive patients with IBS were selected from referrals to Noor hospital, Isfahan from 2008 to 2009; they were randomly assigned to the intervention group or the placebo group (twenty four in the intervention group and twenty two in the placebo group). The intervention group received usual care plus a 8-weekly 2 hours group sessions of coping strategies training whereas the placebo group received usual care plus psychological placebo in four 90 minutes group sessions (bi-weekly). Severity of symptoms, quality of life, anxiety, and depression were evaluated before and two weeks after the intervention using standard questionnaires. Analysis of covariance was used to analyze the data. Findings: Covariance analysis showed significant differences between intervention and placebo groups in severity of IBS symptoms (F = 9.15, P = 0.004). Also the results indicated the significant difference in the percent of the response of patients between the two groups (P = 0.001). Although the findings showed no significant difference between two groups in the levels of depression (P = 0.376, F = 0.8) and anxiety (P = 0.242, F = 1.408) after treatment; quality of life (P = 0.084, F = 3.131) had a trend to be significant. Conclusion: The combination of coping strategies training with standard medical care has considerable effects in the improvement of IBS symptoms. Further studies with larger samples and long-term follow-up are warranted. Key words: Relaxation training, Rational-emotive training, Problem-solving, Cognitive-behavioral therapy, Coping strategies, Irritable bowel syndrome, Quality of life