Neuropsychological (NP) testing of ethnic minority groups indicates that such groups may perform differently from the often used middle-class, white standardization groups. Currently, sensitive neuropsychological test batteries are administered to ethnically-mixed populations in an effort to expose the early existence of subtle cognitive disturbances in those diagnosed HIV-positive. Without revision, the existing NP norms will undoubtedly provide an erroneous picture of cognitive function in those minorities being tested. The extent of this error is compounded by recent findings showing a disproportionately high HIV seroprevalence in African-American and Hispanic groups. The current project has two goals. The first is to develop norms from a sample of 540 male and female African-American subjects on a broad range of neuropsychological measures commonly used to assess neurobehavioral impairment associated with HIV infection. The second goal is to compare matched white and African-American, HIV- positive and HIV-negative subjects on this battery using additional data already being collected at the San Diego HIV Neurobehavioral Research Center (HNRC). A subsample of 100 subjects will be retested after one year to answer important questions regarding normal retest performance. It is expected that comparisons will demonstrate the importance of using minority-based norms in studying neurobehavioral phenomena in HIV-infected minority groups. Specifically, comparisons of the HIV-positive African-American group with the HIV-negative white group may suggest HIV-related impairment rates that are spuriously high. It is further anticipated that actual rates of impairment in white and African-American groups will be comparable when appropriate norms are used for both groups.