Competency repositories have been developed for several years with various objectives: helping to establish competency assessments, helping with recruitment, helping to build training. A repository can bring together the descriptions of several hundred competencies. However, few studies have focused on the structuring of a competency repository. In this paper, the authors propose a general model for a competency repository based on 5 principles. Two of them consist in using a composition relationship to define competencies at several levels of abstraction and a prerequisite relationship to establish prerequisites between competencies. To illustrate the model, an application in the domain of information systems design and implementation is fully developed. The proposed repository, in addition to a new structure, incorporates new competencies compared to existing IS repositories, in particular with regard to strategic management of the IS, development methodologies and techniques, interpersonal competencies, prerequisites coming from basic disciplines. This repository aims primarily to help the organization of academic and professional training and to allow the assessment of personal competencies. This initiative comes from the French network of MIAGE (Méthodes Informatiques Appliquées à la Gestion des Entreprises) masters.