We developed a model immunochromatographic test-system for serological express-diagnostics of pseudotuberculosis. Nitrocellulose membrane sensitized with species-specific antigen, Yersinia pseudotuberculosis thermostable toxin, was used as the immunosorbent. Detection of antibodies to the pathogen was performed using functionalized carbon nanoparticles. System performance was verified in testing of the reference pseudotuberculosis serum. Tests with salmonella, escherichia, and enteral yersinia diagnostic sera and blood serum from a healthy man demonstrated high specificity of the system.