Objective -- As a first step in gathering evidence, this study surveyed school libraries and examined the services those libraries provide in relation to the Universal Basic Education (UBE) program at a primary level. The purpose of this paper is to explore these UBE factors in relation to school libraries in Oyo State, Nigeria. Methods -- A questionnaire was sent to the 33 schools which have a library and information centre staffed by a teacher-librarian, in order to examine library services and the views of those providing them. The questionnaire covers library space, categories of library resources, student activities during library visits, mobile library services, and the teacher-librarians’ perception of the adequacy of the collection and the challenges in the use of library. Results -- Questionnaires were returned by 30 teacher-librarians out of 33, a response rate of 91%. Although pupils across each local government area have the chance to visit school libraries, the system of one short visit per week is inadequate for developing a universal interest in reading and in study skills. Staff responsible for the libraries consider many of the resources to be inadequate or outdated and stock is depleted as pupils borrow books, leaving fewer for those who follow. Conclusions -- As a first step to implementing evidence based practice, this paper describes the primary school library system in Nigeria and provides evidence on how it operates in Oyo State. Teacher-librarians who staff the libraries confirm the inadequacies in the system. They perceive collections to be inadequate and confirm that some pupils in the state have only limited access to library resources. Respondents also believe that they need further training, particularly in computer and information literacy.