A series of reassortant clones with antigenic formulae H2N1 and H2N3 were produced by genetic reassortment performed with the use of an avian influenza virus, A/Pintail Duck/Primorie/695/76 (H2N3) and a high-yield reassortant strain X-67. Preliminary identification of the parent origin of NP and NS genes for 5 reassortants was performed by comparison of the mobilities of virus-specific proteins in polyacrylamide gel electrophoresis. The parent origin of genes of internal and nonstructural proteins for 3 reassortants was identified by partial sequencing. Although the genes of internal and nonstructural proteins of the reassortants originated from high-yield X-67 virus, only H2N3 reassortants were similar to the high-yield parent virus as concerns the level of the virus accumulation evaluated by hemagglutination titration and measurement of the virus protein content.