Irritable bowel syndrome (IBS) is the most commonly diagnosed gastrointestinal condition that comprises 25-50% of all referral to gastroenterologists. IBS causes a great deal of discomfort and distress, but it does not permanently harm the intestines and does not lead to a serious disease, such as cancer. To study the epidemiological aspect, clinical varieties and the response the available treatment in patients whom complaining of irritable bowel syndrome according to Rome criteria in al Diwaniya province in Iraq. Two hundreds sixty four patients with variable clinical presentation of irritable bowel syndrome of different age groups and sexes were fully examined and investigated to exclude the organic disease. We used the chi square calculation in statistical analysis. The mean age of patients in our study was 26.1±1.2 that is mean higher prevalence in younger age group. There is an overall female predominance with more common in married than single. IBS can distribute in smoker and nonsmoker with no significance difference. The most common presentation was the alteration of constipation and diarrhea. Most patients had an exacerbation of symptoms after an emotional stress or eating heavy meal. About 90% of patients fell un satisfactory response to available treatment. This disorder mainly affects young patients of both sexes, so it has adverse effect on the performance and the productive power of country. More advanced treatment modalities adopted in developed countries needed to be evaluated and applied in our country.
