We report a rare primary adrenal leiomyosarcoma in a 30-year-old, human immunodeficiency virus--positive man. This is, we believe, the third documented case in the English literature of this tumor in this site, and the first to be reported in an adult male with acquired immunodeficiency syndrome. The smooth muscle origin of this tumor was apparent by routine microscopy and confirmed by positive immunostaining for smooth muscle actin. The patient is presently well and shows no evidence of recurrence 20 months after surgery. The present findings are discussed with reference to the reported rising incidence of smooth muscle tumors in human immunodeficiency virus--infected patients and the associated etiologic role of Epstein-Barr virus in the pathogenesis of these tumors.