This study aimed to describe adverse effects or reactions by medical devices. There may be unexpected effects caused by medical devices that can often be harmful to the patient. This is defined as a medical device adverse event or adverse effect (MDAE). We should prevent the recurrence of MDAEs by reporting them to regulatory authorities and device manufacturers. This reporting requires that manufacturers check the manufacturing process and update the medical device. However, it is difficult for both patients and medical persons to recognize and report MDAEs because adverse effects can be ambiguous to them in many cases. In addition, many medical persons lack an understanding of the role of this reporting. In Korea, the Ministry of Health and Welfare enacted laws and regulations for MDAE reporting in 2005. However, the number of MDAEs reported was still very small. The Ministry of Food and Drug Safety started the Medical Device Safety Monitoring Center project in 2011, with the purpose of promoting MDAE reporting. Since the Medical Device Safety Monitoring Center project began, the number of reported MDAEs rapidly increased from 137 in 2010 to 6,078 in 2017. Medical persons and device manufacturers should be encouraged to voluntarily report MDAEs and provide useful information. Korea is an important member of the International Medical Device Regulators Forum and leader of the Asia-Pacific Economic Cooperation Regulatory Committee. There should be medical device vigilance with global cooperation.