Rural development has raised attention after the crisis of classical theories of social change and after the European Union has shown great concern for rural spaces in lieu of agricultural firms. These new trends, often summarized as "endogenous and sustainable development", are based mostly on reciprocity as a peculiar, though seldom clarified, way of interaction. A self-sustained development requires the local people's ability to cooperate, to trust each other. In this article the concept of reciprocity is analyzed. The theoretical material is then applied to two farmer cooperatives operating in the Po Delta, Italy, one on the Venetian bank, and the other in the Emilia-Romagna bank, with the aim of verifying whether rural development is an aim of these local actors. Reciprocity results as a foundation principle of cooperation and as a useful tool to understand the strategies of the two cooperatives. The so-called "territorial strategy" (oriented towards the local community) is not carried out as the two cooperatives are committed almost totally to a commercial strategy.