Mobile Applications Stores are content distribution solution dedicated to mobile devices. These solutions are presented in most of the Smartphone available in Brazil and - as a content distribution solution - it has a strong appeal to developers and users. However, since it is a new model of distribution, there is not yet a core bibliography established concerning Usability and Human-Computer Interaction. There are even fewer references when the focus is the Brazilian market and its particularities. This research aimed to fulfill this gap through a theoretical and practical study of the major mobile application s stores available in Brazil. It started with a historical investigation of the development of mobile communication technologies in Brazil and in the world. The purpose of this investigation was to understand the social needs that make it possible the development of Smartphone and mobile application s stores; and how its became the default solution to mobile content distribution, nowadays. After that, a field research was conducted to identify the profile of the Brazilian mobiles application s stores user. A questionnaire was chosen as research s method. The data analysis of the questionnaire s entries enables the identification of this profile; it was used as reference to gather users to an Usability Test. The Test evaluated the methods of search, acquisition and evaluation in the two biggest stores available in Brazil. With these findings it was possible to confirm and identify many of the problems of the stores. Some of these problems are the same reported by other research. It demonstrates that various interactions problems presented elsewhere are present here in Brazil as well. However, the most relevant data concern to Brazilian audience particularity, e.g. the relevance attributed to digital communities, the preferences in store usage and problems regarding the use of unknown terms and labels. At the end of this document there is a list of parameters and recommendations that was developed with the finding of both research techniques.