Four patients having high-level quadriplegia developed elevated serum calcium concentrations (11 to 15.8 mg/100 ml) within three months of injury. All were young males (ages 15 to 19 years) and quadriplegic (C4-C7). Presenting symptoms were nausea, vomiting, polydipsia, polyuria and lethargy. In two patients severe muscle wasting and cachexia with clinical symptoms developed and persisted for several months. Laboratory studies in all patients showed negative calcium balance with hypercalciuria. Reduced renal function was seen in all patients but returned to normal with return of normal serum calcium. Alkaline phosphatase level was normal in three and elevated in one. Serum parathormone levels were normal. Roentgenograms revealed diffuse demineralization. Nephrocalcinosis and soft tissue calcifications developed in one patient. Primary treatment included reduced calcium intake, correction of dehydration, sodium infusion and remobilization. Corticosteroids, oral phosphates, furosemide and mithramycin were used with varying success to control prologned symptoms and severe hypercalcemia.