Although merging clinically within the spectrum of the AIDS dementia complex, vacuolar myelopathy is a pathologically distinct entity detected in up to 30% of autopsied patients succumbing to the late complications of human immunodeficiency virus type 1 (HIV-1) infection. Using immunohistochemistry and in situ hybridization to detect an HIV-1 core protein and viral mRNA, respectively, in tissue sections, and culture isolation to assess infectious virus in tissue homogenates, we found that vacuolar myelopathy was independent of productive HIV-1 infection of the spinal cord and brain. These results indicate that AIDS-associated vacuolar myelopathy is either not related directly to spinal cord HIV-1 infection or involves nonproductive infection and pathobiological processes distinct from those responsible for the multinucleated-cell inflammatory infiltrates that serve as histopathologic markers of productive CNS HIV-1 infection.