Abstract Thirty to 40% of patients with acquired immunodeficiency syndrome (AIDS) have symptoms and signs of neurologic dysfunction. Radiographic and pathologic studies reveal evidence of neurologic involvement in 75% to 90% of cases of advanced-stage human immunodeficiency virus-1 (HIV) disease. Before the introduction of highly active antiretroviral therapies, AIDS dementia complex and opportunistic infections of the central nervous system were frequent causes of global cerebral dysfunction. Focal neurological deficits were most commonly due to toxoplasmosis, primary central nervous system (CNS) lymphoma, or progressive multifocal leukoencephalopathy. Thrombotic events including cerebral infarction and venous thrombosis have been reported in patients with HIV/AIDS. Various hematologic abnormalities have been described that could lead to a hypercoagulable state, including antiphospholipid antibodies; deficiencies of antithrombin III, protein C, and protein S; and increased levels of von Willebrand factor and D-dimer. In the majority of cases of cerebral infarction, there is an associated precipitating event such as opportunistic infection or malignancy. However, vasculopathy has also been described in both adults and children. Furthermore, there are reports of HIV patients with cerebral infarction in whom an HIV-related coagulopathy is identified and other cases where no explanation is found, but only a limited hematologic evaluation has been performed.