The duration of detection of the specific antigen in the cells of the central nervous system (CNS) of mice extraneurally infected with 450, 560 and 4380 LD50 of rabies virus, the Vnukovo-32 strain was studied. The antigen in the CNS cells was detected by the fluorescent antibody technique from the 11th until the 52nd day postinoculation, at 16-34 days being found in 50 to 100% of the experimental animals. In parallel, virus-neutralizing antibody was determined in the blood serum of the infected mice, and their brains were examined for the presence of rabies virus by bioassays. In most cases, serological results correlated with the antigen detection in the brain tissue. At 18, 29 and 34 days rabies virus was isolated from clinically normal mice inoculated subcutaneously, which by all the tests used did not differ from the other experimental animals. The results of the experiments attest to the possibility of rabies virus, the Vnukovo-32 strain, persistence in mice.