In the studies of biogenesis of pyridoxal by Candida albicans 4888,the availability of various organic acids as carbon source was investigated. Carboxylic acids in Krebs' cycle as a sole source of carbon supported the growth of the yeast and the remarkable amount of pyridoxal was produced when malic acid or citric acid was used. It was recognized that fumaric acid was accumulated in the yeast celll especially in the case of malic acid was used as carbon source.