Instructing library users on effective utilization of information resources and services could not be over emphasized in tertiary institutions due to increase in students‟ intake, complexity of library systems, and introduction of information and communication technology in library services. Academic libraries in Nigeria and in particular the Polytechnic libraries are putting much effort to simplify ease of access to retrieve their library resources through the use of catalog cards, online public access catalos OPACs, indexes and abstracts which implies that the issue of availability has been addressed. Meanwhile availability does not translate to use. Therefore, This study seek to investigates the Effects of Library Instructions on the Use of information Retrieval Tools by Students in Polytechnic Libraries in the North-Eastern States of Nigeria with specific emphasis on the type of library instruction programs, effects of library instructions on the use of Information retrieval tools,challenges militating the library instruction, type of Information retrieval tools available in the libraries, level of utilization of Information retrieval tools.Quantitative research method was adopted for the conduct of the study and cross-sectional survey design was used. Simple random sampling technique was used to select respondents to accommodate the different subjects involved in the study. A structured questionnaire was used as the instrument for data collection.The data collected for the study were analyzed using both descriptive and inferential statistics. Copies of questionnaires that were returned were analyzed using one way ANOVA. The study discovered that traditional face-to-face instructions are offered in the Polytechnics and correspondingly has significant effect on students‟ use of information retrieval tools and other library resources. It was equally revealed that manual retrieval tools are available in all the Polytechnic libraries while the electronic search tool is available in only one Polytechnic. Catalog card report the very frequently used retrieval tool by Polytechnic students.The study concluded that, library instruction prepares polytechnic students toward effective utilization of retrieval tools expending the strategies and techniques acquired on how to search and retrieve information materials in their libraries. So therefore, Polytechnic libraries need to reevaluate library user instruction to strengthen the use of both manual and electronic retrieval tools. It is recommended that library instructions should be incorporated into the Polytechnic curriculum to affect changes in students‟ library behaviour