While taking antiretroviral therapy, 30%–60% of people living with HIV (PLWH) experience neurocognitive impairment (NCI). To determine NCI prevalence among Iranian PLWH, by the computerized Vienna Test System, 63 adults living without HIV and 63 Iranian PLWH aged 18–50 years (M = 35.3, SD = 7.9) were assessed for cognitive function. NCI was determined by receiver operating characteristic curve cutoff points based on the adults living without HIV. Associations between demographics, HIV serostatus markers, and mean T-scores were investigated. Performance differences were tested by including significant covariates in an analysis of covariance. NCI prevalence rates were 57.14% in PLWH and 19.05% in adults living without HIV. Global neurocognitive performance and all cognitive domains were significantly different between the groups, except for visual memory and selective attention. In Iran, NCI prevalence parallels that reported in PLWH worldwide. There should be a strategy to screen Iranian PLWH for NCI.