Objective - Development of a Russian test kit for validating the cytomegalovirus infection by immune blotting. Tasks - Selection of the optimal conditions for obtaining the viral lysate, its electrophoresis, and electrophoretic transfer of protein complexes onto nitrocellulose membrane and its subsequent processing. Selection of a conjugate and a solution, optimization of other reagents, determination of the optimal conditions of the test. Material and methods. The following procedures were used when designing a new test system: polyacrylamide gel electrophoresis in sodium dodecyl sulfate (conditions for denaturation by Laemmli), electrotransfer of the separated proteins from the gel onto a solid support (nitrocellulose membrane) or blotting; detection of proteins transferred to the membrane using enzyme immunoassay followed by visual evaluation of the test results. Results. A Russian test kit for detecting class G antibodies to individual antigens of cytomegalovirus using immune blotting (Western Blot) was designed. The new test kit has diagnostic efficiency not conceding one of its analogues, the Anti-CMV (IgG) Western Blot test kit ("Euroimmun AG", Germany). Meanwhile, it is characterized by lower cost and a number of consumer characteristics that ensure more efficient use of the kit.