ABSTRACT - Drug approval-patent linkage is the practice of linking drug marketing approval to the patent status of the originator's product and not allowing the grant of marketing approval to any third party prior to the expiration of the patent term unless by consent of the patent owner. Article 18.9.5 of Korea-US Free Trade Agreement requires that Korea introduce the linkage system in drug marketing approval. However, Korea is unfamiliar with the linkage system. In addition, there have been lots of arguments over the impacts of this system on Korean pharmaceutical industry and pharmaceutical market in the future. This report investigated the linkage systems of the US and Canada. The US and Canada have implemented drug approval-patent linkage system since 1984 and 1993, respectively. Both countries have patent lists for drug approval-patent linkage on which originators are required to list patent on substance, product, and use of their drugs. Generic or follow-on drug applicants must contain a certification regarding each patent listed that relates to the referenced drug. If the patent holder files suit for patent infringement within 45 days of notice of application, drug approval is not allowed for several months - 30 months in the US and 24 months in Canada. Both countries have amended their systems after having experienced unexpected results such as listing improper and additional patents, multiple patent litigations and delayed generic entries. After reviewing the US and Canada's experiences, we suggested three principles needed in implementing the system: protecting patent holder's right; promoting generic drug development and marketing; monitoring the process and the effect of the system.