The objective of this study is to evaluate the use of standardization and classification rules, proposed by the CEAGESP, by peach producers and wholesalers and to identify the effects of this procedure on the supply and commercialization of the fruit. The methodology used included qualitative study and analysis of study cases. Information was gathered through interviews with producers from the state of São Paulo and with the wholesalers of the Entreposto Terminal de São Paulo. Most producers are optimistic about the use of standardization and classification rules and emphasize that their implementation is the reason behind the success of peach commercialization. They invest in improving the quality of the product by updating, whenever possible, the technologies used in the production and post-harvest processes. Among the wholesalers, a preference for and a valorization of the classified peach was observed, although these agents say that the market does not yet recognize the benefits of the standardization and classification rules. The conclusion of this work is that use of the standardization and classification rules suggested by the CEAGESP functions as a support tool in the management of the peach commercialization process.