This paper analyzes the participation of small farmers in the fresh fruit and vegetable supply systems of supermarkets in Mexico, using the case of small-scale guava farmers in the state of Michoacán. Three findings emerge. (1) The most important determinant of access of these farmers to more modern markets is their territorial (spatial) context and the way in which those territories interact with different markets, followed by fixed capital assets. Farm size, education and participation in organizations are not significant determinants. (2) Farmers working in the more modern markets compared to those in the traditional markets, are labor-constrained and overuse chemical inputs to a lesser extent. (3) Farmers that have accessed the more modern market channels, have substantially higher net income per hectare. Policies and projects aimed at promoting the inclusion in more modern markets of small-scale farmers such as those producing guava in Michoacán, must act on the territorial dimension of the problem of inclusion/exclusion, and not restrict themselves to actions aimed at improving the supply chains or the capacities of the households or their farms and organizations.