The clinical and laboratory responses to steroid therapy in four patients with sarcoidosis, hypercalcemia, and renal insufficiency are presented. The predominant complaints of these patients were anorexia, nausea, vomiting, and abdominal pains simulating ulcer distress. The diagnosis of sarcoidosis was confirmed in each case by lymph node biopsy. Administration of steroids produced a prompt fall in the level of serum calcium with complete relief of symptoms, despite evidence of persistent mild renal insufficiency in three cases. Long-term steroid therapy has been necessary in these three cases to maintain an asymptomatic and normocalcemic state. The history of a fifth patient is presented to illustrate the difficulties which may be encountered in making the diagnosis of sarcoidosis. In recognized cases of sarcoidosis, studies of the serum calcium and renal function would appear desirable if irreversible renal complications are to be prevented.