Abstract: In this paper we used chirasil-val capillary column gas chromatography as analytical method to study whether there is an observable stereoselective radiolysis of D-phenylalanine and L-phenylalanine molecules under gamma irradiation. Our experimental configuration differs from A. S. Garay where both D-and L-amino acids are separated. As they should exist together with the same concentration, the same absorption dosage of irradiation,furthermore, the D-phenylalanine and L-phenylalanine molecules are set at the same condition of chemical environment to get rid of the effect of unknown impurities.Our result comes out negatively to the hypothesis. In the range of experimental error the stereoselecti ve radiolysis of D-and L-phenylalanine under gamma irradiation is not observed.