Irritable bowel syndrome (IBS) affects as many as 14% of high school-aged students. Symptoms include discomfort in the abdomen, along with diarrhea and/or constipation and other gastroenterological symptoms, which can significantly impact quality of life and daily functioning of patients. Emotional stress appears to exacerbate IBS symptoms suggesting that mind-body interventions reducing arousal may prove beneficial. Often symptoms can be traced to childhood and adolescence, making the early manifestation of IBS important to understand. The current study focuses on young people aged 14-26 years of age with IBS. The study will test the potential benefits of Iyengar yoga (IY) on clinical symptoms, psychospiritual functioning and visceral sensitivity. Yoga is thought to bring physical, psychological and spiritual benefits to practitioners and has been associated with reduced stress and pain. Through its focus on restoration and use of props, IY is especially designed to decrease arousal and promote psychospiritual resources in physically compromised individuals. Sixty-four IBS patients aged 14-26 will be randomly assigned to a standardized 6-week biweekly IY group-based program (1.5 hour sessions) or a wait-list usual care control group. The groups will be compared on the primary clinical outcomes of IBS symptoms, quality of life and global improvement at post-treatment and 2 month follow-up. Secondary outcomes will include visceral pain sensitivity assessed with a standardized laboratory task (water load task), and psychospiritual variables including coping, self-efficacy, mood, acceptance and mindfulness. It is hypothesized that IY will be safe and feasible: with less than 20% attrition; and the IY group will demonstrate significantly improved outcomes compared to controls, with physiological and psychospiritual mechanisms contributing to improvements; clinical treatment gains will be maintained at 2 months following yoga.