The occurrence of occupational illnesses and injuries has been seriously underestimated in Korea. This underdiagnosis and underreporting of occupational illnesses and injuries subsequently contribute to difficulties in performing effective control of occupational hazards and implementing intervention programs to protect workers. An Inchon model for an occupational disease surveillance system was constructed using multiple data sources. Available data were obtained from medical providers' reports, hospital medical records, medical examination data of employees, and environmental measurement data. This Jnchon model was constructed with the following procedure: 1. assembled multidisciplinary staff 2. geographic targeting was to Inchon 3. established community liaison 4. collected related data to establish the magnitude of problem 5. selected, recruited, and trained case reporters 6. developed mechanisms and guidelines for reporting 7. received, screened, and prioritized case reports 8. analyzed data from case reports and field investigations 9. made and disseminated recommendations 10. evaluated the feasibility of the system. An information system based on the Internet for the occupational disease surveillance was also constructed to support the case reporting of occupational diseases. 133 cases of occupational diseases were collected in Inchon from 1 January to 31 December 1998. These cases included cumulative traumatic disorder, occupational asthma, occupational contact dermatitis, allergic pneumonitis, occupational cancer, noise-induced hearing loss, and pneumoconiosis. These data were different from the previously reported data The occurrence pattern of occupational diseases obtained from this surveillance system will be useful for preventing occupational hazards and for enforcing occupational disease prevention programs. Our experiences in establishing this surveillance system may be also used in other regional settings.