Despite great advances and a significant understanding of HIV pathogenesis, no curative treatment modality currently exists. Since baboon bone marrow cells (BBMC) are believed to be resistant to the human immunodeficiency virus, researchers have recently transplanted BBMC into two patients with AIDS, a process known as xenotransplantation. The purpose of this paper is to provide a comparative analysis of human and baboon hematopoiesis, followed by a review of the pathophysiologic effects of the HIV on the human hematologic and immune systems. The two protocols implemented since 1994 are discussed, including an overview of the potential risks and benefits and implications for nursing practice.