To elucidate whether serum alpha and beta-carotene and retinol levels are related with the risk for amyotrophic lateral sclerosis (ALS), we compared serum levels of alpha-carotene, beta-carotene, and retinol (vitamin A), measured by HPLC, in 40 patients with amyotrophic lateral sclerosis (ALS) and 87 matched controls using an isocratic high performance liquid chromatography technique. The mean serum alpha and beta-carotene, and retinol levels did not differ significantly between the 2 study groups. These values were not influenced by the clinical form (spinal vs bulbar) of ALS, and they did not correlate with age, age at onset, and duration of the disease. These results suggest that serum alpha and beta-carotene and retinol concentrations are unrelated with the risk for ALS.