The development of genetic engineering allowing the direct manipulation of DNA molecules in vitro, called recombinant technology, has offered production of many biologically active compounds. The greates success in recombinant DNA techniques has been obtained in the aera of manufacturing hormones, e.g. insulin and beta-endorphin. Presently bovine somatotropin genetically engineered (rBST) has been used for increasing milk yield and growth rate in cattle. The aim of the rewiev is to discuss applicability of rBST in dairy cattle, with some remarks on efficacy and safety of the use of rBST for milk yield. Notes on the most recent research tools provided by biotechnology — growth hormone enhancement by monoclonal antibody (immunomodulation of GH) and immunoneutralization of somatostatin, are included.