To elucidate the possible role of carotenoids and vitamin A as risk factors for Alzheimer's disease (AD), we compared serum levels of β-carotene and α-carotene, and vitamin A, measured by isocratic high performance liquid chromatography, of 38 AD patients and 42 controls. The serum levels of α-carotene did not differ significantly between AD patients and control groups. However, the serum levels of β-carotene and vitamin A were significantly lower in the AD-patient group. These values did not correlate to age, age at onset or score on the MiniMental State Examination. Weight and body mass index were significantly lower in AD patients than in controls. These results suggest that low serum β-carotene concentrations in AD patients could be related to a deficiency in dietary intake of this provitamin, although its possible relationship with risk for AD could not be excluded.