In recent years, user experience (UX) has gained importance in product development because of the increased product complexity, the availability of innovative technologies, etc. UX evaluation methods and tools developed up to now keep users’ emotions in the right consideration; nevertheless, they do not exploit mental models at best. This research aims at developing a UX evaluation method based on the so-called interaction-related mental models, a specific type of mental models focused on interaction matters. The description of the method proposed here considers also its adoption in the field and the results are compared with those obtained by a classic usability evaluation method. Although the scope of the proposed method is quite limited now (the UX evaluation focuses on CAD software packages only), the research results seem very promising. Nevertheless, this limitation will be overcome in the near future.