This paper deals with the function of farm land. The objective is to demonstrate that the socio-environmental function of land ownership has a different and broader role than mere administration. According to the current Brazilian Constitution, owning land gives a right to property that is bound by the social and environmental requirements prescribed by the law. Therefore, the nature of rights over land property has changed. The traditional capitalist ownership has been socialised, having as its organising and limiting principle the well-being of present and future generations. The new juridical structure is based on this foundation.