The preconditioning allows to beef cattle gaining weight. The objective was to evaluate the economic feasibility of this practice, considering diets, average daily gain and livestock´s buy-sale prices. The evaluated diets were prepared by a specialist in animal nutrition for preconditioning seven stages of animal production; male calves, female calves, heifers, steers, thin cows, young bulls and bulls. In order to correlate the diet´s information five livestock producers were interviewed and, as a consequence, the characteristics of the elements involved in this operation were clarified. Subsequently, based on the above information, economic analysis was performed to assess the viability of the producer to adopt any of the diets. Net income per animal unit was as follows: $345.36 for bulls; $325.72 for steers; $95.44 for calves; $86.39, $ 41.53 calves, heifers $ 12.48 while for the lean years was $ 8.91. It is concluded that the practice of preconditioning is economically feasible.