The study aims to identify the importance of the reference service in the search and retrieval and how to use sources and references, dictionaries and encyclopedias as well- as declaration, importance of reference service in the Sudanese public libraries researcher used the descriptive analytical method, both the survey and the historical method and the statistical method in order to describe the information and data specific to one study, as well as for data analysis and interpretation down to draw result. The researcher used in the collection of information and data references and periodicals and the Internet and the interview, also used the questionnaire. The most result following: -1. Beneficiaries lack of training on how to use information sources. 2. 58% of the study sample is specialized in library and information. 3. That 52% of respondents named study ways that reference service is the corresponding evaluation. 4. 42% of the study sample has access information from the library