Bakground. Monoclonal antibodies are reliable and convenient tool for the diagnosis of human pathologies. Most often they are used as conjugates with fluorescent or other labels. The classical approach of creating such conjugates reduces chemical reactions using monoclonal antibodies protein base. However, for a number of manufacturing monoclonal antibodies conjugate followed by embedding tags in the antigen binding site, which leads to reduction or complete loss of specific activity of the conjugate. The way out of this situation could be the synthesis of fluorescent conjugates, methods of carbohydrate chemistry through spatially distant from the active site of the antibody oligosaccharides. The purpose of the study - to show the fundamental possibility of chemical modification of the oligosaccharides monoclonal antibodies ICO series and get to their base fluorescent conjugates. Materials and methods. We used monoclonal antibodies panel ICO series of high purity. Oligosaccharides monoclonal antibodies oxidized to aldehyde groups, is reacted with a hydrazine derivative of biotin and streptavidin-conjugated flyuoristsiinom. The resulting complex was used for the direct reaction immunofluorescence. Results. All modified monoclonal antibodies retain binding specificity to target cells inherent to native antibodies. Conclusions. This may be an alternative method for conjugating a fluorescent label with monoclonal antibodies to protein synthesis methods which lead to loss of activity of the conjugate.