Objectives: An international multicenter, prospective, non-interventional, 2-month study characterized acute pain attacks in patients with irritable bowel syndrome (IBS). Methods: Adult patients meeting the Rome III IBS diagnostic criteria with a history of 3 pain attacks per month participated in a survey that captured daily and episodic information regarding IBS symptoms and pain attacks for 2 months. Acute pain attacks were defined as a sudden onset or increase in the intensity of IBS abdominal pain with a minimum intensity of 4 (0-10 scale). Results: The majority (84%) of the 158 patients taking the survey were women with a mean age of 41 years and time since IBS diagnosis of 5 years. The median pain attack frequency was 5.4 attacks per month and was significantly higher in the IBS with diarrhea (IBS-D, 6.4 per month) group vs. the IBS with constipation (4.4 per month) and the IBS with mixed pattern (5.5 per month) groups (P<0.019). The median pain attack duration was 2.8 h and the median intensity score was 7. The majority of pain attacks resulted in defecation (78%), and occurred more often in IBS-D patients than in other subgroups. The majority of pain attacks (63%) interfered with work and/or daily activities. Medication to manage pain attacks was used by 44% of patients during 29% of attacks. Although used by less than half of all patients, medication helped 66% of attacks treated. Conclusions: The frequency of severe pain attacks was 1.4 per week and the majority affected daily activities. However, most of the pain attacks were untreated in IBS patients. Pain attack management is an unmet need of IBS treatment.