Key Clinical MessageA whirl sign on contrast‐enhanced abdominal CT scan is indicative of intestine twisted around the mesenteric vessels, and is observed in cases of strangulated obstruction, signaling compromised intestinal circulation. In cases of intestinal volvulus, surgery is necessary to untwist the affected bowel, and resection is necessary if necrosis is present.AbstractA 31‐year‐old Japanese man presented with acute lower abdominal pain and vomiting. Contrast‐enhanced abdominal computed tomography (CT) revealed a 1440‐degree clockwise torsion of superior mesenteric artery and a whirl sign. Intestinal volvulus in adulthood with a background of malrotation is extremely rare. Contrast‐enhanced CT is effective for diagnosis.