The review article information on the current status in the research regarding bispecific antibodies. The theoretical and methodical aspects of preparation of heterohybridomas secreting bifunctional monoclonal antibodies are discussed in details. The question of purification of the antibody fraction with dual specificity is also addressed. The possible application of bispecific antibodies in human medicine for immunodiagnostics and aimed immunotherapy is described. (Fig. 7, Ref. 22.).