From 1989 to 1995, 25 ICU-patients underwent cholecystectomy for acute acalculous cholecystitis (AAC). Preoperative diagnosis remains difficult and ultrasound imaging proved to be the most valid instrument for early diagnosis. Predisposing factors like duration of respiratory failure, extent of surgery, amount of blood loss and mode of analgesia were analyzed. Undelayed surgical treatment was important to avoid further complications such as gangrene or perforation of the gall bladder.