Treatment of HIV-infected patients with highly active antiretroviral therapy (HAART) has altered the natural history of human immunodeficiency virus (HIV) infection by decreasing the frequency of opportunistic infections and altering the expected frequency of hematologic complications and AIDS-related malignancies. Thrombotic thrombocytopenic purpura and thrombosis resulting from protein S deficiency are relatively rare complications of HIV in the United States in patients taking HAART, but are frequent in the developing world where these drugs are not available. Cytopenia, particularly anemia, are more common and result both from bone marrow failure and peripheral destruction. Hodgkin's and non-Hodgkin's lymphoma are still problematic in patients with advanced disease with high viral loads. This review will examine and discuss the diagnosis and management of the hematologic complications of HIV.