The invention relates to the R-enantiomer of N-carbamoylmethyl-4-phenyl-2-pyrrolidinone (R-Carphedon) of pharmacological value. The method of its preparation includes the N-alkylation of 4(R)-phenyl-2-pyrrolidinone with ethyl bromoacetate in the presence of a strong base and the treatment of intermediate N-ethoxycarbonylmethyl-4(R)-phenyl-2-pyrrolidinone with ammonia.