Six patients receiving total parenteral nutrition (TPN) developed hypercalcemia and acute pancreatitis. Four were long-term home TPN patients, and two were short-term hospital TPN patients. Causes of pancreatitis other than hypercalcemia were not found. The etiology of the hypercalcemia remained unclear and in particular was not due to calcium infusion or hyperparathyroidism. In 4 patients in whom it was measured, the plasma parathyroid hormone was normal (in 2) or nondetectable (in 2). Hypercalcemia and pancreatitis subsided with discontinuation of TPN. Thus, some patients receiving TPN develop hypercalcemia, and in some of these pancreatitis ensues.