The reference section of every library remains an important arm of such library. It contains materials needed for teaching, learning, community development and research. However, studies have shown that most of these materials are rarely consulted by library users, hence, the rationale of the present study which investigated the extent to which reference materials are accessed and utilized by the undergraduates of library and information science (LIS), Taraba State University (TSU), Jalingo. Six research objectives with corresponding research questions were considered and answered. The descriptive survey method was adopted using a total population of 133 final year undergraduates of LIS, TSU, Jalingo. Furthermore, the complete census technique was employed to study the entire population. A fifty-eight (58) items questionnaire was used for data collection. 133 copies were distributed, but 127 (95.5%) copies were returned and found suitable for data analysis. The data analysis was done using descriptive statistics of mean scores and frequency counts. Findings revealed a high extent of accessibility of a good number of reference materials. Few of these materials were reported to be utilized to a high extent leading to a relationship between the extent of accessibility and utilization. However, numerous challenges were identified to be facing the accessibility and utilization of reference materials by the undergraduates. The study concludes that the extent of accessibility determines the extent of utilization which all proved to be high in the library studied. It was, however, among other things, recommended that the management of university libraries should intensify efforts to improve the number and quality of reference materials provided and make them accessible to their users.