Biliary sludge develops commonly in critically ill patients and may be associated with biliary colic, acute pancreatitis or acute cholecystitis. Sludge often resolves upon resolution of the underlying pathogenetic factor. It is generally diagnosed on sonography. Treatment of sludge itself is unnecessary unless further complications develop. Acute acalculous cholecystitis also develops frequently in critically ill patients. It may be difficult to diagnose in these patients, manifesting only as unexplained fever, leukocytosis or sepsis. Sonography and hepatobiliary scintigraphy are the most useful diagnostic tests. Management decisions should take into account the underlying co-morbid conditions. For many patients, percutaneous cholecystostomy may be the best management option. Cholecystostomy may also provide definitive drainage as patients recover and underlying critical illness resolves.