ABSTRACT This article propose the extent of an inspection method called RECOEXTDI (REcorrido COgnitivo EXtendido para aplicaciones de Television Digital Interactiva) to evaluate the usability of applications supported on Interactive Digital Television (IDT) environments. The former method has three basic inputs: The original cognitive walkthrough method, the characteristics of TDI applications, and early testing performed in a TDI laboratory. To assess RECOEXTDI, it is described a case study in which an evaluation of the usability of a TDI application is made, by using the traditional and the extended method. In this way, the results obtained are compared with the implementation of the two methods described. The RECOEXTDI method allowed finding a larger number of usability problems in shorter time, compared with the traditional method. KEYWORDS: Inspection methods, Interactive digital TV (IDT), RECOEXTDI, Usability evaluation.