Abstract: Objective To explore the feasibility to titrate rabies viruses in prmiary cerebral cortex neurons of mice.Methods The primary cerebral cortex neurons of mice were prepared and inoculated by median mouse intrace rebral lethal dose(100M ICLD₅₀)of CVS stra in and the infections were con firmed by mimuno fluorescent and RT-PCR detection.Then the median cell culture infectious dose(CC ID₅₀)was determined on the cultured neurons.Results The results showed that prmiary cerebral cortexneurons were successfully prepared and could be infected by rabies viruses efficiently.The titer of CVS stra in was 10^4.5CCID₅₀/0.1mL,and the or iginal inuculum was 10^4.5MICLD₅₀/0.03mL.Conclusion The titer titrated in the cultured neurons was equal to the original titer of MICLD₅₀.It implies that prmiary cerebral cortex neurons might be served as a potent technique for titrating the rabies viruses in vitro.