The common diagnoses in low back pain are lumbar strain, lumbosacral radiculopathy, osteoarthritis, degenerative disc disease, spinal stenosis, and sacroiliac joint dysfunction. Unusual causes of low back pain that have been previously identified include abdominal aortic aneurysms, pelvic neoplasms, and retroperitoneal hemorrhages. This report describes a case of back pain that was apparently caused by a duodenal ulcer. A 54-year-old man with no significant medical history presented with a complaint of mid to low back pain (T10-L2), which was diagnosed as joint dysfunction. A comprehensive treatment program was prescribed and the patient was instructed to return to clinic in 4 weeks. Three weeks later, he experienced a syncopal episode followed by coffee ground emesis. He immediately sought medical attention at an emergency room, where he was admitted to the hospital with a diagnosis of upper gastrointestinal bleed. Esophagogastroduodenoscopy showed a large duodenal ulcer, and the patient underwent vagotomy and pyloroplasty. He returned to his physiatrist's office 3 weeks after hospital discharge with minimal back pain. The cause of the back pain proved to be referred visceral pain from his duodenal ulcer. This case is presented to reemphasize the need to include the uncommon phenomena in the differential diagnosis of low back pain.