Severe symptomatic hypercalcemia is a rare event in children with malignancies. Up to now there is limited experience treating childhood hypercalcemia with bisphosphonates in addition to calcitonin. We report a 5-year-old boy with acute lymphoblastic lymphoma who presented with malignant hypercalcemia at diagnosis. The maximal serum calcium concentration was 15.2 mg/dl (3.81 mmol/l). Conventional therapy with forced diuresis and furosemide failed. Calcitonin (10 IU/kg/24 h i.v. for 2 days) and pamidronate (1 mg/kg over 2 hours i.v.) were used successfully without adverse effect lowering the serum calcium level within 24 hours to normal values. We recommend the use of calcitonin and pamidronate as first-line therapy together with forced diuresis and furosemide in childhood hypercalcemia secondary to malignancies as it is rapidly effective and has no significant side effects.