In the following discussion I will examine the application of Wittgenstein's concept of family resemblance to genre theory. Despite its popularity among literary theorists, there is sometimes a discrepancy between the loose concept of family resemblance, at least in its negative-radical version, and the practical assumptions made about genres. In order to overcome the inadequacies of existing applications of the concept, I will propose two ways in which Wittgenstein's concept can be fruitfully applied to genre theory. First, by using certain working hypotheses in cognitive psychology, based on the concept of family resemblance, I will argue that literary genres are perceived as structured categories, with a ‘hard core’ consisting of prototypical members. These prototypical members are characterized by the fact that they bear a relatively high degree of resemblance to each other. Second, by focusing on the analogy between the internal structure of literary genres and that of families one can establish a ‘genealogical’ line of literary genres, i.e., the series of writers who have participated in shaping, reshaping and transmitting the textual heritage established by the ‘founding father’ of the genre, including the dialectical relationship of ‘parents’ and ‘children’ in genre history.