A process for producing L-phenylalanine at high rates of formation and in good yields is provided which comprises allowing a microorganism which belongs to the genus Nocardia and is capable of producing L-phenyl-alanine from phenylpyruvic acid or a salt thereof and an amino group donor to act upon an aqueous solution containing phenylpyruvic acid or a salt thereof and an amino group donor selected from the group consisting of ammonium salts and ammonia in a hydrogen gas atmosphere.