Efficiency of various protocols of specific immunoglobulin treatment was evaluated in golden hamsters inoculated with two Far Eastern tick-borne encephalitis (TBE) strains. After a low therapeutic dose (0.1 ml) of immunoglobulin, corresponding to total dose (60 ml) per course, all parameters (survival, immunogenicity, pathomorphology of the brain) deteriorated in animals infected with both strains. A higher dose (0.2 ml) corresponding to total dose of 120 ml notably improved all the studied parameters. The efficiency of specific immunoglobulin depends on the clinical and pathogenetic characteristics of TBE, determined by the properties of TBE strains. The results validate therapy and prevention of TBE by high-titer immunoglobulin in adequate total dose, monitored by blood analyses for TBE antigen and evaluations of the time course of IgM antibodies.