This study was intended to help workplaces set up an occupational health & safety management system by investigating the certification of the system and by conducting a questionnaire to survey the necessity, purpose, effect and promotion of the system. The occupational health & safety management systems generally adopted in Korea are OHSAS 18001 and K-OHSMS 18001, which are the PDCA model, such like the quality and environment management system. Because these standards have a compatibility with other management systems, individual or integral certification is available. A telephone questionnaire was conducted with 30 workplaces in Kyeonggi Province and Incheon Metropolitan City, which have been certified for the occupational health & safety management systems (OHSAS 18001, KOSHA 2000, and/or K -OHSMS 18001). About 92 percent of them were large-sized workplaces with over 500 employees. For the question on the necessity of the system, most of the respondent answered very necessary. The purposes of the certification were to control the risks in safety and health, to have a systematic approach for accident prevention and sustainable improvement, and to comply with a range of regulations voluntarily, in that order. Most of the answers to the question on the effect of the system were prevention of accident. For the question on the promotion of the system, the most prominent answer was reduction in the workers compensation rate.