Serum vitamin A was determined in a cross-sectional study of 100 HIV-positive and -negative tuberculosis patients and 144 blood donors. Tuberculosis patients were seen again after 2 months of treatment. Mean vitamin A was lowest among tuberculosis patients co-infected with HIV, and was lower among HIV-positive than -negative donors. Mean vitamin A rose significantly at 2 months in HIV-negative patients, and not in -positive patients. HIV infection was the strongest predictor of low vitamin A. Vitamin A deficiency is common in tuberculosis and HIV infection, particularly in those patients who are dually infected, and nutritional supplementation may be beneficial.