The management of patients with acute calculous cholecystitis has changed during recent years. The etiology of acute cholecystitis is still not fully understood. Infection of bile is relatively unimportant since bile and gallbladder wall cultures are sterile in many patients with acute cholecystitis. Ultrasonography is first choice for diagnosis of acute cholecystitis and cholescintigraphy is second best. Percutaneous puncture of the gallbladder that can be used for therapeutic drainage has also diagnostic qualities. Early cholecystectomy under antibiotic prophylaxis is the treatment of choice, and has been shown to be superior to delayed surgery in several prospective trials. Mortality can be as low as 0.5% in patients younger than 70-80 years of age, but a high mortality has been reported in octogenerians. Selective intraoperative cholangiography is now generally accepted and no advantage of routine cholangiography was shown in clinical trials. Percutaneous cholecystostomy can be successfully performed under ultrasound guidance and has a place in the treatment of severely ill patients with acute cholecystitis. Laparoscopic cholecystectomy can be done safely in patients with acute cholecystitis, but extensive experience with this technique is necessary. Endoscopic retrograde drainage of the gallbladder by introduction of a catheter in the cystic duct is feasible but data are still scarce.