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The aim of the study was to evaluate the effects of adding ractopamine (RAC) and amino acids (AA) to the diet on growth performance, carcass characteristics, commercial cuts yield, meat quality and residues in liver and muscle. Ninety-two crossbred castrated pigs (97.96 + 2.32 kg) were randomly assigned to one of two dietary treatments: a Control diet with 0 mg kg -1 of RAC and a RAC+AA diet with 10 mg RAC kg -1 , for the last 27 days. Pigs of RAC+AA group had greater average daily gain (ADG), gain to feed ratio (G:F) and final bodyweight (P≤0.05) and tended to have lower average daily feed intake (ADFI) (p=0.084) than Control pigs. Carcasses from RAC+AA animals were heavier than controls (P≤0.05). Dressing percentage and backfat depth were not affected (P>0.05) by diet. Weights of head and skin were not different between treatments, but RAC+AA pigs had greater weights of boneless center loin, ribs, boneless ham and shoulders, tenderloin, neck, rear shank and trimmings (P≤0.05). The addition of RAC+AA did not affect crude protein and water content of loins but tended to reduce ether extract (p=0.08). Drip loss, pH, and cooking loss in pork were not different. Shear force tended (p=0.092) to be higher in RAC+AA. No differences in L* and b* color coordinates were found but a* values were lower in RAC+AA. Hue angle and chroma did not differ. Confidence limits at 90% were determined for residues in muscle and liver, obtaining values from -2.7 to 3.4 μg kg -1 and -6.7 to 10.6 μg kg -1 , respectively, both below the limits established by Codex Alimentarius. Dietary inclusion of RAC+AA at 10 mg RAC kg -1 in the diet of finishing pigs improved growth performance and produced heavier carcasses and commercial cuts, had minimal effects in pork characteristics and produced pork and liver with RAC residues below limits from Codex Alimentarius . El objetivo de este estudio fue medir el efecto de la adicion de ractopamina (RAC) y aminoacidos (AA) en la dieta sobre el crecimiento, caracteristicas de la canal, rendimiento de cortes comerciales, caracteristicas de la carne y residuos en higado y musculo. Noventa y dos cerdos castrados (97,96 + 2,32 kg) fueron asignados aleatoriamente a dos dietas: un Control con 0 mg kg -1 de RAC y a una dieta RAC+AA con 10 mg RAC kg -1 , durante los ultimos 27 dias de engorda. Los cerdos RAC+AA tuvieron mayor ganancia diaria de peso (GDP), eficiencia de conversion alimenticia (ECA) y peso final (P≤0,05) y tendieron a comer menos (P=0,084). Las canales del grupo RAC+AA fueron mas pesadas (P≤0,05), pero son diferencias en rendimiento y espesor de grasa dorsal. El peso de cabeza y plancha no fue diferente, pero el grupo RAC+AA tuvo pesos mayores en el lomo de centro, lomo vetado, costillar, pulpa paleta, pulpa pierna, pernil y sobras (P≤0,05). La adicion de RAC+AA no afecto la proteina cruda y materia seca del lomo, pero redujo el extracto etereo (P=0,08). No hubo diferencia en la perdida por goteo, y por coccion, ni en pH, pero la fuerza de corte tendio (P=0,092) a ser mayor en RAC+AA. No hubo diferencias en L * y b * pero si en a *, siendo mas bajo en RAC+AA. El angulo Hue y Chroma no difirieron. El intervalo de confianza al 90% determino que los residuos en musculo e higado fueron de -2,7 a 3,4 mg kg -1 y -6,7 a 10,6 mg kg -1 , respectivamente. La inclusion de RAC+AA en la dieta de cerdos de engorda, produjo canales y cortes comerciales mas pesados, con efectos minimos en caracteristicas de la carne y con residuos de RAC bajo el limite del Codex Alimentarius.