Since 1955 simultaneous presentation of acute appendicitis und acute cholecystitis have been described. These cases are understood as concomitance on the one hand and as imitation or induction of acute cholecystitis due to acute appendicitis. In laparoscopic surgery for inflammatory diseases, in particular acute cholecystitis, exploration of the entire abdomen should be more than cursory. In remarkable postoperative courses after cholecystectomy in acute cholecystitis, acute appendicitis should be taken into account if it could not be excluded intraoperatively.