Based upon the provision of limitation of copyrights, libraries may provide the document delivery service which supplies copies of journal articles and book chapters owned at other libraries by request of users. However, more proactive information service is required as more users want to use the digital delivery of documents published overseas. This study reviews copyright law of Korea and international conventions related to the document delivery service. It then examines foreign cases to see how overseas information centers clear copyrights. Finally this study suggests that copyright clearance methods be adopted to make a proactive information service. Through those methods, a new information service model may be planned, which meets various information needs while protecting copyright.