The purpose of this study is to develop a practical model for enhancing cooperative virtual reference services of public libraries in the nation. The research methods include an examination of model cases from Europe and the V.S. and also an electronic questionnaire survey of 375 public librarians (73% response rate). The study results suggest the need for `a collaborative virtual reference room` which consists of the collaborative reference database, virtual reference desk, guidance and instruction designed by age groups and/or subjects.