The objective of this study is to assess the serum concentration and the urinary depletion of vitamin A in patients with AIDS with acute illness (hospitalized) and without acute illness (clinic attenders); and to examine the relationship of serum and urinary retinol levels with weight loss, patient survival, CD4 count, fever, and liver function. Serum and urinary retinol of 26 patients from the AIDS clinic hospital of the University of Alabama at Birmingham (UAB) were measured using HPLC. Mean serum retinol was lower in hospital patients than in clinic attenders, although the difference was not statistically significant. However, urinary retinol loss was significantly higher in hospital patients than clinic patients (0.09 ± 0.12 vs. 0.04 ± 0.12, p=0.0193). There were significant correlations between urinary retinol excretion and body weight loss in clinic patients and between urinary retinol loss and high serum bilirubin levels in hospital patients. A significantly higher proportion of hospital than clinic patients lost body weight during the last month before recruitment into the study (p=0.039). Further a significantly higher proportion of those who lost weight subsequently died than survived (p=0.015). Urinary loss of retinol was significantly predicted by increased body temperature (p=0.0069) and decreased CD4 count (p=0.0454) in clinic patients. No single variable predicted significantly the urinary retinol loss in hospital patients. The presence of acute illness in hospital patients with AIDS appeared to be a risk factor for low serum retinol and increased urinary excretion of retinol. Greater urinary retinol loss and more severe illness are associated with body weight loss and death.