Description: We were observed transformation 4-ethylpyridine and 2-methyl-5-ethylpyridine by fungus Beauveria bassiana ATCC 7159. Stereoselective oxidation of methylene group leading to the optically active (-)-(1-hydroxyethyl)pyridine was shown. Besides, the hydroxylation of methyl groups and the oxidation of the heterocyclic ring in the nitrogen atom to the respective primary alcohols and N-oxides were observed. Keywords: transformation, 4-ethylpyridine, 2-methyl-5-ethylpyridine