The prevalence of vitamin A deficiency and its association with dietary retinol intake in patients with AIDS was assessed in a cross-sectional study. Sixty eligible patients with AIDS provided serum samples that were analyzed for retinol content. Exclusion criteria included current use of vitamin supplements (57% of the 140 willing to participate) and pregnancy (none). Past dietary intake was determined using a standardized food intake frequency questionnaire. The prevalence of hyporetinemia was 22%. This was a 241-fold greater prevalence than that of a representative sample of the U.S. population, after adjusting for age and sex. There was a positive association between serum retinol status and dietary intake, but 27% of those with adequate intake had serum retinol levels below the normal range. These findings suggest that regardless of intake, patients with AIDS may represent a population at considerable risk of vitamin A deficiency.