The duty of confidentiality, high costs, complicated procedure and the absence of licensor’s duty of cooperation for the registration all contributed to the under-utilization of the license registration system in Korea, which in turn resulted in the ratio of registration of licenses. Therefore, practically most of the licenses are unregistered, which render the status of the licensee extremely unstable because of the lack of perfection of license through registration: It makes the licensee impossible to resist the assignee upon assignment of patents by licensor to a third party, to restrict, upon bankruptcy of the licensor, the exercise of the power of termination of license of the bankruptcy trustee, or to challenge the assignee upon assignment of patents by the bankruptcy trustee. These problems of the protection of the status of the licensee are not only disadvantageous for individual licensees but also greatly hamper the social and economical sense of justice, making the task of protecting the licensee more urgent and necessary. Therefore, the methods and strategies of protecting the rights of the licensee must be institutionalized systematically, but the issue of the most desirable method of the protection of the licensee must be approached only after properly investigating and answering matters that require serious consideration when devising methods of protection of the licensees. As parts of these considerations, this thesis presents, based on researches in Japan, the following three perspectives in detail: ① balancing of conflicting interests, ② harmony with other laws and regulations and ③ procedural efficiency.