The computed tomographic (CT) appearance of two cases of sigmoid colon volvulus is described. Both underwent plain abdominal radiographs, contrast enema, and CT. The findings of sigmoid volvulus at CT were characteristic, having a whirl pattern of the dilated sigmoid loop around mesocolon and vessels and a bird-beak aspect of the afferent and efferent segments. CT may be valuable in a case of unusual clinical or plain film presentation as an alternative to contrast enema.