Background: Vitamin D status affects immune function and thus may affect the progress of HIV infection. Objectives: Our goals were to assess vitamin D intake and status in subjects with HIV infection and in matched control subjects and to determine whether HIV infection was associated with vitamin D insufficiency. Design: Plasma 25-hydroxyvitamin D [25(OH)D] concentrations and vitamin D intake were measured in a cross-sectional study of members of the Reaching for Excellence in Adolescent Health (REACH) cohort. Results: The subjects were aged 14-23 y; 74% were female, and 72% were black. Mean (±SE) vitamin D intake from food was 30% greater (P = 0.023) in HIV-positive subjects (295 ± 18 IU/d; n = 237) than in HIV-negative subjects (227 ± 26 IU/d; n = 121). The prevalence of vitamin D supplement use was 29% (104 of 358 subjects) and did not differ significantly by HIV status (P = 0.87). Mean plasma 25(OH)D did not differ significantly (P = 0.62) between the HIV-positive (20.3 ± 1.1 nmol/L; n = 238) and HIV-negative (19.3 ± 1.7 nmol/L; n = 121) subjects, nor was HIV status a significant predictor of plasma 25(OH)D when multiple regression analysis was used to adjust for other variables. The prevalence of vitamin D insufficiency [plasma 25(OH)D ≤ 37.5 nmol/L] in the subjects was 87% (312 of 359 subjects). Conclusions: HIV infection did not influence vitamin D status. The prevalence of vitamin D insufficiency in both HIV-positive and HIV-negative REACH subjects was high, perhaps because these disadvantaged, largely urban youth have limited sun exposure. © 2006 American Society for Nutrition.