Ten cases of acute acalculous cholecystitis, presenting to one university affiliated institution, are described. These patients were predominantly older males with either overt vascular disease or a predisposition to vascular disease and were without the usual precipitating factors described for acalculous cholecystitis. Ultrasonography was helpful in making the diagnosis and early laparotomy revealed gangrenous cholecystitis in all patients, three of whom had perforated gall-bladders. Although there was no mortality, morbidity was high, and patients stayed in hospital a mean of 10.5 days. A vascular aetiology seems likely and early surgery is recommended to avoid the high mortality reported in the literature. It seems that this form of acalculous cholecystitis is different to that seen in other clinical settings.