Introduction. Stigma is one of the main reasons why patients with obsessive-compulsive disorder (OCD) delay seeking help and treatment. The esTOCma e-health app is a serious game that has been developed to overcome this stigma and lack of knowledge about OCD by providing tools for seeking professional help. The objective of this study is to analyze the usability, satisfaction and dropouts reason associated with the use of the esTOCma app. Method. 555 participants with an average age 39.24 years (SD= 15.78) (64.3% women) assessed the usability of the app after using it until the game was over (days of use Mean (SD) = 17.78 (15.58); range: 0 to 95 days). Participants assessed the usability through the System Usability Scale (SUS) and satisfaction through an ad hoc questionnaire composed of four items (i.e., perceived usefulness, learning, duration of the app, recommendation of the app) with a Likert scale of four points. In addition, 155 participants who had drop out of the app were interviewed individually to assess the reasons for abandonment. Results. Usability assessed with the SUS obtained a mean score of 86.35 (SD=12.48) in a range between 42.5 and 100, which is interpreted as a perceived excellent app. Regarding the perceived usefulness, obtained 3.48 (SD=0.61) representing a perception of the app between useful and very useful. Moreover, most users (92.8%) felt that the app helped them learn about OCD between a lot and quite a bit. 77.36% of the participants considered the app duration very adequate and adequate, and 84.3% of the participants indicated that they would recommend the app very much. Regarding the reasons for drop out, after the categorical analysis of the interviews through an inter-judge analysis, 35.3% of participants stated they did not have time to use it, 25.6% forgot that they had to use the app, 18% had problems with the app and notifications, 17.9% reported that its duration was excessive, and 3.2% thought it was not what they expected based on the categorical analysis of the interviews through an inter-judge analysis. Discussion. The main findings in this study suggest that there is a high level of usability and satisfaction associated with the esTOCma application, and the main dropout causes were due to participants’ characteristics (“didn’t have time to use it”) and behavioral reasons (“forgot that they had to use the app”).