Agile Software Engineering approaches gain more and more popularity in today"s development organizations. The need for usable products is also a growing factor for organizations. Thus, their development processes have to react on this demand and have to offer approaches to integrate the factor "usability" in their development processes. The approach presented in this paper evaluates how agile software engineering models consider activities of Usability Engineering to ensure the creation of usable software products. The user-centeredness of the two agile SE models Scrum and XP has been analyzed and the question of how potential gaps can be filled without loosing the process" agility is discussed. As requirements play a decisive role during software development, in Software Engineering as well as Usability Engineering. Therefore, different User Centered Requirements that ensure the development of usable systems served as basis for the gap-analysis.