In older people, medicines are considered appropriate when they have an evidence-based indication, are well-tolerated and cost-effective. However, inappropriate prescribing (IP) is a common and significant healthcare problem in elderly people in Korea as well as in the world. IP in old people is highly prevalent but preventable. Screening for IP is highly desirable, since detection and correction are simple and worthwhile. Until now, Beers' criteria for IP dominate the international literatures, although they have some defects. The 2002 version of Beers' criteria-independent of diagnosis includes 48 different categories of either single medications or multiple medications of a similar class identified as IP, and the 2002 version of Beers' criteria-considering diagnosis contains 19 different categories containing possible drug-disease interaction. Successful approaches to optimizing prescribing have been either educational or administrative. More research specially focused on the IP in the elderly is needed.