The immunoperoxidase test was used to detect influenza virus in cells of a chorionallanthois shell of infected chicken embryos. Application of monoclonal antibodies D8 and A11 in the analysis has permitted detecting reproduction of type A (subtypes H1N1, H2N2, H3N2) viruses, the PGA titre of the respective allantois liquids being not lower than 1:16. The matrix protein and hemagglutinin, detection of which underlies this analysis, were found on the cell membrane, in the perinucleus region and as cytoplasmic inclusions.