Acute abdominal pain is a common presenting complaint in older patients. Presentation may differ from that of the younger patient and is often complicated by coexistent disease, delays in presentation, and physical and social barriers. The physical examination can be misleadingly benign, even with catastrophic conditions such as abdominal aortic aneurysm rupture and mesenteric ischemia. Changes that occur in the biliary system because of aging make older patients vulnerable to acute cholecystitis, the most common indication for surgery in this population. In older patients with appendicitis, the initial diagnosis is correct only one half of the time, and there are increased rates of perforation and mortality when compared with younger patients. Medication use, gallstones, and alcohol use increase the risk of pancreatitis, and advanced age is an indicator of poor prognosis for this disease. Diverticulitis is a common cause of abdominal pain in the older patient; in appropriately selected patients, it may be treated on an outpatient basis with oral antibiotics. Small and large bowel obstructions, usually caused by adhesive disease or malignancy, are more common in the aged and often require surgery. Morbidity and mortality among older patients presenting with acute abdominal pain are high, and these patients often require hospitalization with prompt surgical consultation.