Ultrasound is the initial imaging modality of choice for the evaluation of suspected acute gallbladder disorders, and is often sufficient for correct diagnosis. CT also plays a vital role, however, in the evaluation of acute gallbladder pathology. CT is particularly useful in situations where ultrasound findings are equivocal. CT is also extremely valuable in the assessment of suspected complications of acute cholecystitis, particularly emphysematous cholecystitis, hemorrhagic cholecystitis, and gallbladder perforation, which are often very difficult diagnoses to establish at sonography. If CT is the initial imaging test performed in a patient with abdominal pain of uncertain etiology, recognition of the various disorders described in this article may eliminate the need for further imaging and facilitate appropriate management.