Fifty-eight patients with acute caecal volvulus are presented. Fifty-five patients had plain abdominal radiographs taken shortly after admission and the diagnosis was suspected in 29 (53%). Forty-five of these radiographs have been reviewed and, in retrospect, the diagnosis could have been made in 40 (89%). The dilated caecum usually assumes a 'comma-shape', retains its haustral markings and may be located anywhere within the abdomen but is most frequently seen centrally or occupying the left upper quadrant. Diagnostic difficulties were found in patients with peritonitis and when there was gross small bowel dilatation. Accurate diagnosis is vital as delay in the surgical treatment of this condition may lead to an increased incidence of gangrene of the caecum and a higher mortality.