This study investigated mentoring as a determinant for the development and growth of Library and information science professionals in federal university libraries in South/South, Nigeria. Descriptive survey research design was used for the study. The population used consists of 115 professional librarians from all the federal university libraries in south/south, Nigeria. Four research questions were used for the study. The data was collected using structured questionnaire and data were analyzed using simple percentage and frequency counts. The instrument was validated by experts and trial tested with the results of the reliability co-efficient of 0.87 was obtained. The study revealed that mentoring has overwhelming benefits to information science professionals among which is relieving mentors of some duties and encouraging succession. It also increases harmony and creates good work environment in libraries. The study also shown that insincere desire of mentors to share knowledge with mentee as one of the major obstacles affecting adequate mentoring in university libraries in Nigeria. Based on these findings, the university library management is advised to encourage their old or experienced librarians to consistently engage their young ones in mentoring programme and library managers should also see mentoring as a factor that can make or mar the commitment of librarians and therefore make appropriate plans of using it as a panacea to retain their staff.
Keywords: Mentoring, Library, Information science, determinant, Universities, Growth and Development