The landmark report "To Err is Human", by the Institute of Medicine in 1999, cited studies that found that at least 44,000 people and potentially as many as 98,000 people die in United States hospitals each year as a result of preventable medical errors. So, medical errors were a big issue in U.S. And U.S. Congress make the legal system for preventing medical errors. The medical mistakes can be prevented by designing and utilizing the medical errors database system through reporting adverse events. But medical providers are reluctant to report their adverse events and participate in quality review activities for fear of liability or injury to their reputations. This problem can cause to prevent the accumulation of a sufficient number of adverse events. But if medical providers have the privilege of exemption from liability when they report their adverse events on the Patient Safety and Quality Improvement Act, report system for the medical errors database system may operate properly. Through a comparative study on the Patient Safety and Quality Improvement Act of foreign countries, we can draw implications for enacting the Patient Safety and Quality Improvement Act in Korea.