This article describes and analyses the changes in the landholding structure and forms of production in the valley round the Aconcagua river during the 19th century, following the gradual changes in the insertion of the región in the agricultural exports model. The first stage, up to the first crises in the wheat markets, is marked by an increase in the áreas sown with grain, thanks to an extensión of irrigation and better communications with the mining regions in the North of Chile and the port of Valparaíso. This process was accompanied by a gradual división of the large estates but without a transformation in the forms of production. The second stage, linked to the grain export crises in the Central Valley, shows a diversification of the crops grown in the valley for the internal and foreign markets, based on the intensive use of the land, which leads to the creation of agroindustries of an intermedíate level.