Recently, subject specialized service has been suggested as a solution to overcome a difficulty of library management and to meet the quickly changing needs of library users. Introduction of subject specialized service is raised to be introduced to special libraries and efficient management system is required. However, systematic study on the subject specialized service is very rare. This study investigates and analyzes how subject specialized service is operated in korean special libraries and how subject specialist librarians recognize them. In order to analyzes and investigate, 8 special libraries was selected to survey general management of subject specialized service, recruitment and training issues of subject specialist librarian, their duties and overall evaluation and problem of subject specialized service. Finally the study attempts to suggest development strategies in order to improve subject specialized service in special libraries.