The present invention discloses an optically active complex of L-valine N-benzoyl-L-alanine, comprising one mole each of L-valine and N-benzoyl-L-alanine. N-benzoyl-L-alanine is found to react selectively with L-valine to form the novel crystalline complex even in the presence of D-valine, other amino acids, and impurities present in synthetic DL-valine and in the crude L-valine from the hydrolysis of protein and fermentation. The optically active L-valine N-benzoyl-L-alanine is used as an intermediate for the optical resolution of DL-valine and for the purification of L-valine.