The article considers the problem of genre attribution of the short story The Root of All Evil by Graham Greene, which is defined as novella by the French criticism and as a story by the Russian criticism, and correlation of its poetics with the genre model. The importance and topicality of solving this problem lies in the fact that this is the first study of the genre specificity and poetics of one of Greene’s short stories written in the comic mode, which opens the prospect of a comprehensive study of the whole body of his short prose (not studied yet). The research is based on the theory of the genre (M. Bakhtin, N. Leiderman, R. Welleck and O. Warren, etc.), according to which the genre is a form of artistic cognition of the world, has genre memory (the semantic core of the genre) and sets the parameters of the artistic world-modeling and reading of the text, and also uses the genological, textual, structural-analytical and narratological principles of analysis, which allowed to make the following conclusions. First, the presence in the work of such characteristic features of the novel genre as an unusual case or incident underlying the plot; one dominant storyline and the dynamism of unfolding of events with their accumulation; an unexpected turn of the plot (novelistic pointe) and a comic beginning inherent in a significant number of short stories. Secondly, the semantic content of the work corresponds to the artistic model of the novelistic genre, which is characterized by a mockery of the undue, defective, false (in this case religious dogmatism) and the assertion of a healthy and full-fledged element of being. The method used in the work and the results obtained are promising both for further study of Graham Greene’s small prose and for similar fields of research.