Effective communicable disease surveillance systems are the basis of the national disease prevention and control. Following the increase in emerging and re-emerging infectious diseases since late 1990s, the Korean government has strived to enhance surveillance and response system. Since 2000, sentinel surveillance, such as influenza sentinel surveillance, pediatric sentinel surveillance, school-based sentinel surveillance and ophthalmological sentinel surveillance, was introduced to improve the surveillance activities. Electronic reporting system was developed in 2000, enabling the establishment of national database of reported cases. Disweb, a portal for sharing communicable disease information with the public and health care workers, was developed. In general, the survey results on usefulness and attributes of the system, such as simplicity, flexibility, acceptability, sensitivity, timeliness, and representa-tiveness, received relatively high recognition. Compared to the number of paid cases of national health insurance, reported cases by national notifiable disease surveillance system, and various sentinel surveillance system, the result of the correlation analysis was high. According to the research project conducted by KCDC, the reporting rate of physicians in 2004 has also greatly improved, compared with that in 1990s. However, continuous efforts are needed to further improve the communicable disease surveillance system. Awareness of physicians on communicable disease surveillance system must be improved by conducting education and information campaigns on a continuous basis. We should also devise means for efficient use of various administrative data including cause of death statistics and health insurance. In addition, efficiency of the system must be improved by linking data from various surveillance system.