Biological drugs are the most rapidly growing group of medicinal agents. In addition to hormone and vaccine products, the significance of drugs produced using genetic engineering has increased in numerous indications, especially in oncology. Furthermore, they have significantly contributed to the treatment of inflammatory musculoskeletal as well as cutaneous and intestinal diseases. Their use is limited by parenteral administration, immunogenicity, uncertainty about possible severe adverse effects and especially the high price of the drugs. The cessation of patent protection of the original brand pharmaceuticals, and marketing of biosimilar drugs are expected to lower the prices of the original biological, as well.