The present paper analyzes the scale and the technical efficiency of the agricultural cooperatives in the Paraná state, and identifies the factors that are related with their efficiency. The methodology is based on Data Envelopment Analysis (DEA), and discriminant analysis. Results demonstrate that large agricultural cooperatives are more efficient than the small ones. The main factors that influence the efficiency are own capital (equity) and smaller payment periods. In synthesis, to reach larger levels of competitiveness, the agricultural cooperatives need to develop better defined capitalization practices.