- This paper presents the main findings of a research that Cermes - Bocconi has carried out on behalf of some industrial firms (Barilla, Campari, Coca-Cola, Ferrero, Kraft, Parmareggio) and with the contribution of some commercial firms (AgorÀ- Poli, Auchan, Carrefour, COOP Estense, GS, SELEX, SIGMA, SMA). The main goal of the research was to discover the importance of assortment policies in industrial and retail marketing. First, we verify the hypothesis that explain the continued increase in assortment dimension with the dependence of retail marketing upon manufacture's contribution leading to a pour service to consumers. Then we verify that the convergence of assortment is the main cause of hypermarket crisis as well as a great contributor to the reduction of store loyalty. This paper aim to introduce a series of empirical research on the subject of retail assortment.Keywords: assortment, intertype-intratype competition, diversification, assortment quality, channel partnershipParole chiave: assortimento, intertype - intratype competition, diversificazione, qualitÀ dell'assortimento, collaborazione di canale