Not much is known about the structure of working memory in atypical development. We undertook a detailed comparison of the functional organization of working memory in HIV-infected (n = 95; Mage = 7.42 years), and HIV-exposed (n = 86; Mage = 7.36 years) children, together with an uninfected, unexposed typically developing comparison group (n = 92; Mage = 7.05 years). Participants were in their first year of formal education. Within-group comparisons of five models showed that a four-factor model with separate verbal and visuospatial storage and processing accounted for the typically developing group, while working memory was structurally undifferentiated in the HIV-affected groups.