this study focuses on the economic rationality of large landed estates in the iberian peninsula. it assumes these estates submit to a rational land use, that is sensitive to economic change. its goal is to discuss the main criteria for economic management of landed estates in southern portugal during the last decades of the nineteenth century: namely profit, risk, rent, and patrimony. a multiple-criteria programming model, farming economic accounts, and compared analysis are used in developing a case study. the article concludes for a patrimonial logic within which a policy for compromise between income and risk was followed.