The assessment process is one of the most important issues in the learning process and in many case it is the process that defines the instruction sequence because it measures the performance of the student in the educational process. During recent decades the inclusion of TICs in the teaching-learning process have facilitated addressing the diversity of student and teacher features. Technologies to enhance learning have allowed the different ways of learning and teaching that coexist in the educational context to be adapted through user modeling and adaptation processes. Our purpose in this paper is to introduce ". IRTT" (item response theory tool), an adaptive tool based on item response theory to generate assessment according to the student competence level, in the context of a learning management system (LMS), in particular. LRN [2].