Primary small bowel volvulus in adults is a very rare condition, and it is defined as torsion of all or a large segment of the small intestine and its mesentery in the absence of any preexisting etiologic factors. Proper management of the patients suffering from a strangulated obstruction depends on making an early and accurate diagnosis. Timely treatment is crucial to prevent gangrene. A 49-year-old man who had a history of previous abdominal surgery was admitted to our hospital with complaints of acute abdominal pain. Simple abdominal x-ray showed multiple dilated loops of small intestine in the mid-abdomen. Enhanced abdominal computed tomography showed the distended small bowel loops and longitudinal tapering of the collapsed bowel loops. We carried out diagnostic laparoscopy to confirm the cause of suspected mechanical ileus. It revealed strangulation of the small bowel at the terminal ileum due to clockwise torsion of the bowel loop. There were no adhesions or congenital anomalies in the peritoneal cavity. The torsional segment was spontaneously reduced with minimal handling, and the strangulated portion was resected. The patient was discharged from hospital on postoperative day 6. Primary small bowel volvulus in adults is a very rare malady; if the diagnosis is uncertain, then diagnostic laparoscopy is a valuable tool for making the definitive diagnosis and administering prompt treatment.