We describe a 73‐year‐old HIV negative patient who presented with symptomatic hypoglycemia. Over the course of several months she was diagnosed with three human herpesvirus‐8 related diseases: multicentric Castleman's disease, primary effusion lymphoma and Kaposi's sarcoma. No improvement was observed following cytotoxic therapy and she died 16 months after her initial presentation. The etiology of the hypoglycemia remained obscure over the course of this patient's disease. This case is the first report of a patient with three human herpesvirus‐8 related diseases, and the first report of severe hypoglycemia as the presenting symptom of any of these diseases. Am. J. Hematol. 65:310–314, 2000. © 2000 Wiley‐Liss, Inc.