Current trends in e-Learning focus mainly on personalizing and adapting the learning environment and learning process. Although their increasingly number, theses researches often ignore the concepts of capitalization and reuse of learner experiences which can be exploited later by other learners. Thus, the major challenge of distance learning is to introduce a reuse approach of learning situations in e-Learning systems. Based on these observations, the aim of our research is to capitalize the learner experiences in order to be memorized and reused. PELSYS, acronym of Personalized E-Learning SYStem, is interested in the Case-Based Reasoning (CBR) mechanism in order to reuse previous experiences to offer to the current learner the best suited experience to his needs. This experience should be already validated and evaluated by other learners having similar learning profiles. In fact, our contribution concerns the ontology modeling of different e-Learning elements (the learner, the domain, the learning experience) and proposing an efficient approach, which is based on the integration of the ontological reasoning in the CBR mechanism, for calculating the similarity between situations.