Perfluorochemicals (fluorocarbons, PFCs) are the ones possible to use oxygen vector in biomedical sciences. Their structure, chemical and physical properties are fully described. The use of PFCs in medicine and biotechnology is presented. Possible areas of application of perfluorochemicals in biochemical engineering are discussed. Pure liquid or emulsified PFCs are used in the bioreactor cultures of microbial, plant or animal cells to improve the oxygen (or carbon dioxide) delivery with simultaneous reduction of hydrodynamic shear stress.