Abstract. The main goal of this work is to identify a set of design criteria for Web applications taking into account the users' emotions. The results are based on the analysis of a user study with 50 participants who tested six Web interfaces, each one designed to elicit a specific emotion (hate, anxiety, boredom, fun, serenity, love). The design criteria applied to the six emotion-based Web interfaces were drawn from the results of a previous survey, which involved 57 different users, on the relationships between emotional state and Web interfaces. This initial survey asked the users to indicate the emotions most often associated with Web interaction, and then assign each emotion with some specific Web design characteristics. The resulting design criteria can form the basis for a set of emotion-related guidelines for Web application user interfaces.