SUMMARY
Usability has become a fundamental aspect of the development of a software product for being a primordial feature of quality. This concept is linked to the use nature of software and can be evaluated through ausability test. This testing is made quantitatively through measurement for two of the features (efficacy and efficiency) that define it. The satisfaction as a third associated feature is of a qualitative kind which estimation is subjective given that it depends on the absence of discomfort by the test user during its interaction with the product. This article is the result of a research that proposes an approach for the estimation of the satisfaction in user tests involving facial expression analysis. This idea is supported in the development of a software system for the emotional monitoring of a user during a test.