The present invention relates to a method for preparing pregabalin{ (S) -3- (aminomethyl) -5-methylhexanoic acid}, which is useful for the prevention and treatment of seizure disorders, pains, and psychiatric disorders. According to the present invention, pregabalin can be prepared in a high enantiomeric excess of 99% or more, without an additional step of separating or purifying its enantiomer.