This study was conducted in four (4) University libraries,(two states and two federal) in the south œ south zone of Nigeria to provide information on the perception of both librarians and readers on the influence of information source parameters (obsolete information sources and availability of relevant information sources), as well as personal characteristics of librarians (attitude and experience) on readers ability to retrieve information. The study used survey design to determine by means of a one item in a four point likert scale questionnaire, the influence of these variables on reader‘s ability to retrieve information. Four (4) hypotheses were tested. Out of the total of 700 library registered undergraduate students, only 698 students and all the 9 librarians answered and returned usable questionnaires. Statistical Package for Social Sciences (SPSS} and t-test was used for data analysis. The major findings are that all the four hypotheses tested, rejected the null hypotheses, which means that all these variables influence reader‘s ability to retrieve information. This calls for the librarians to improve upon their personal characteristics as well as the provision of relevant information sources if quality reference services are to be attained. Based on these findings, recommendations were made, the major ones of which are the automation and internet connectivity of the reference section of the library, provision of current and relevant information, online access to information sources/e-library and re-training of librarians especially those librarians working in the reader‘s services libraries.