The traditional literature about the Castilian agriculture has interpreted the sale of baldíos as one of the main causes of the decline of Castile during the seventeenth century. The sale obligated the peasant to buy the land if he wanted to continue working on it. Many of these lands were marginal and poor soils, so the growth of production cost would have led many farmers to the ruin and poverty. Many of them had to migrate to other regions, causing a deep fall of agriculture production, the main production activity of Castile’s economy at that period of time. This paper shows that Castile entered in decadence not because the baldíos were sold but because the reasons inviting people to use more land and to increase production during the first half of the sixteenth century disappeared around 1590. Instead of seeing exclusively the new costs faced by the farmer after the sale, this paper explores what happened with revenues from plowing more land. Baldíos was an institution that helped an increase of production through expansion of land and labor. Who was the owner of these lands seem to be indifferent in order to explain the amount of production factor used on agriculture. If baldíos was not the reason that provoked a huge migration in the Castilian countryside, then, who was the responsible?. Problems to maintain the returns from agriculture, and not the unexpected increase in the price of land, were the real cause of the final crisis at the end of the sixteenth century.