Most of the university libraries in Korea provide digital reference service(DRS), but the use of DRS is very low. The low usage of DRS seems to result from the lack of subject librarians, of staff, of public relations, and of managers’ enthusiastic attitude and understanding of DRS. It is difficult to solve these problems because of the poor circumstances in universities. The collaborative digital reference service(CDRS) is a solution to these problems. Not only CDRS costs little but also can provide reference services in many different subject areas. Though subject specialist librarian, user-friendly system interface, system programs and administrative supports are necessary to implement CDRS, the education and training of the subject specialist librarians is the most important work to be done in the university library situation in Korea.