Six cases of splenic flexure volvulus were studied over a 14-year period. The patients were aged 15-62 years. Five of the six patients were mentally retarded, lifelong residents of a long-term-care institution. Two patients had congenital absence of normal colonic attachments; the other four patients had elongated mesocolons, presumably from chronic constipation. All patients underwent abdominal radiography, followed by a barium enema study. In the appropriate clinical setting, radiographic diagnosis of a splenic flexure volvulus is suggested when the following are seen: (a) a markedly dilated, air-filled colon wtih an abrupt termination at the anatomic splenic flexure; (b) two widely separated air-fluid levels, one in the transverse colon and the other in the cecum; (c) an empty descending and sigmoid colon; and (d) a characteristic beak at the anatomic splenic flexure at a barium enema examination.