In summary, patients with HIV infection may develop a bewildering variety of electrolyte and acid-base disturbances. Hyponatremia from many causes is common and associated with an increased mortality. Potassium disorders are frequent, with hyperkalemia, even to life-threatening levels, more common than hypokalemia. Disturbances in calcium and uric acid homeostasis are less frequent. Acid-base disorders also complicate the clinical course of AIDS and, as with the electrolyte perturbations, may result from HIV infection itself, the illnesses associated with AIDS, or medications.