The hematologic manifestations of HIV infection include morphologic abnormalities of peripheral blood and bone marrow changes. Laboratory abnormalities, including measures of coagulation, serum vitamin B12 levels, and positive Coombs's test, are seen with HIV infection and may not carry the same clinical consequence as when noted in non-HIV infected populations. Antibodies to circulating red blood cells, platelets, and granulocytes may represent alterations in autoimmunity or nonspecific HIV-induced B-cell stimulation, but they do not necessarily correlate with development of peripheral blood cytopenias. The advent of commercially available hematopoietic growth factors has allowed greater insight into specific host-virus-drug interactions that may be important in regulating viral growth and expression. Novel clinical approaches using hematopoietins alone or in combination with antimicrobial, antiviral, and antitumor drugs represent exciting developments in the treatment of HIV infection.