In this review contemporary trends in the application of monoclonal antibodies are presented. There is discussed antibody reengineering for humanization of mouse monoclonal antibodies to avoid anti-globulin reaction of patient. Recent modifications of antibody fragments are also outlined. The most common antigenic structures exposed to antibody attack are characterized. Some aspects of human monoclonal antibody production are briefly described. Three most promising therapeutic antibodies - bispecific antibodies, immunotoxins, and radiolabeled immunoconjugates - are presented.