Acute acalculous cholecystitis is an uncommon but very serious illness, that, if undiagnosed, may lead to gallbladder perforation and death. The condition has numerous causes that result in bile stasis and ischemia leading to inflammation and infection in the gallbladder wall. The bedside diagnosis may be difficult, especially in critically ill patients. Current imaging techniques including ultrasonography, computer tomography, and radionuclide cholescintigraphy are very helpful. Depending on the clinical situation, the gallbladder should either be drained by a surgical or percutaneous cholecystostomy under local anesthesia or removed.