Hypercalcemia is a rare complication of malignancy in children. We present two children, one of whom is the youngest reported, with CALLA+ B-cell acute lymphoblastic leukemia (ALL) who developed hypercalcemia at the time of diagnosis and were treated with relatively low-dose (0.5 mg/kg) intravenous pamidronate successive to conventional therapy. No major side effects were encountered except transient hypocalcemia and hypophosphatemia, which were easily managed by replacement therapy. Bisphosphonate therapy was found to be beneficial for the treatment of resistant hypercalcemia associated with ALL, even at relatively low doses.