Immunization has been one of the most effective measures preventing from infectious diseases. However, children routine vaccination rate of Korea was 68.2% and it was not higher than expected. Korean government revised the School Health Law for every primary school children to submit the vaccination certificate record from 2005. It is quite important national Infectious disease prevention policy to keep the immunizations rate high and monitor the immunizations rate continuously. To do this, National Institute of Health introduced the National Immunization Registry(NIR) Program at 2000. Objective : The aims of this study was to evaluate the Immunization Registry program which has been implementing since 2000 at the Public Health Centers(PHC). Methods : The mail survey was done from November 2001 to January 2002. 169 (69%) Public Health Centers among 244 PHC were responded. Results : The respondents of PHC sud the Immunization Registry(IR) program had reduced the workload (18.5%). 69.2% said they inputted the immunization data into the IR program after the shots were given. 86.5% said they hadn´t checked or retrieved the children lists who had missed the scheduled immunization. Only 17.2% said the speed of internet for the R program was good. It showed that 20% of respondents hadn´t written down documents, records on immunization any more. Even there were a lot of negative results, the respondents of PHC thought that the IR program was effective. They especially agreed that the IR program could make the job accurate (81.5%), convenient (71.3%), and reduced the chances of making mistakes (71.3%), increase the service quality (78.5%). And they were well adapting the job process of the IR (79.63%). Bivariate analysis showed that the software program was the important determinants of IR success. The only Bit Computer software program has been evaluated to be less satisfactory than the Integrated (Posdata operating system + Bit software) program. Other variables, such as age, duration of present job, and location of PHC (metropolitan, small city, rural area) were not significantly related. Conclusion : It seemed that the success of NIR might depend on the software program. Because Integrated program, which has been developed from 1994, include not only the general operating and management program for PHC but also IR program. It was natural to prefer Integrated program to Bit software program. So we can suggest that it is essential for the NIR to be successful that not only the immunization software program but also hardware equipments and public health information system should be further improved.