N-Carbamoyl-D-alpha-amino acid amidohydrolase (D-carbamoylase) was found to distinguish stereochemistry not only at the cl-carbon but also at the beta-carbon of N-carbamoyl-D-alpha-amino acids. The enzyme selectively acted on one of the four stereoisomers of N-carbamoyl-alpha,beta-diastereomeric amino acids. This simultaneous recognition of two chiral centers by D-carbamoylase was useful for the fine stereoselective synthesis of alpha,beta-diastereomeric amino acids such as threonine, isoleucine, 3,4-methylenedioxyphenylserine and beta-methylphenylalanine. The stereoselectivity for the beta-carbon was influenced by the pH of the reaction mixture and by the bulk of the substituent at the beta-carbon.