Hypercalcemic crisis represents a medical emergency. If conservative treatment is ineffective, low calcium bath or zero calcium bath hemodialysis are good alternatives. We report 4 patients treated with calcium free acetate hemodialysis because of hypercalcemic crisis due to breast cancer, hepatocellular carcinoma, cirrhosis of the liver and immobilisation with hydrochlorothiazids' medication. Following 3 h of hemodialysis, serum calcium concentrations fell from a mean value of 3.96 (range 3.53-4.46) mmol/l to 2.71 (2.28-3.12) mmol/l. In 2 patients rapid clinical improvement was achieved and in one oliguric patient diuresis started spontaneously during hemodialysis. One patient died from gram-negative sepsis. In 3 cases the subsequent conservative treatment was sufficient to maintain serum calcium levels within the normal range. Together with the previously reported cases (5 patients treated by hemodialysis with low dialysate calcium and 3 patients by hemodialysis with calcium free dialysate) our experience indicates that hemodialysis is an effective and safe therapy for hypercalcemic crisis.