The demand for agricultural information system are small but expanding in Korea. Use of information system in farm extension hilps both farmers and extensionists. This study undertakes surveys of literature on information system and extension to finds their relationship. Use of the information system can make extension service more effective if it is developed to meet following factors; 1) consider real farm problem; 2) solve the problems; 3) generate more values than costs; 4) consider real farm environments; 5) comprehensive enough to consider all relevant knowledge domain; 6) sensitive enough to meet the changes in farm environment; 7) educational and easy to learn; 8) easy to maintain.