Various methods for obtaining oxytocin from its recombinant precursor oxytocinoyllysine were studied. For splitting off the C-terminal lysine residue in oxytocinoyllysine, the carboxypeptidase B and an analogous carboxypeptidase from king crab hepatopancreas were used. Ammonolysis of oxytocinic acid methyl ester proved to be the most efficient method for the last stage of the oxytocin preparation. Reversed-phase HPLC was used for the product analysis at each stage of the recombinant oxytocinoyllysine conversion into oxytocin.