A job analysis of subject specialist librarians is an important source providing information about definition of a job, development of a curriculum, administration of human resources, criteria of employee training, and deciding institutional and individual objectives. This study analyzes a job of subject specialist librarians in Korea, and divides their jobs into 7 duties and 58 tasks. the 7 duties are as follows; A. a development of subject information resources, B. a management of information resources classified by subjects, C. a research support service classified by subjects, D. Liasion activity of library users, E. an education of subject classification for library users, F. library management, G. personal development of classified subject areas.