This research was conducted in the poultry company Agropecuaria Santa Maria S.A.C., located in the district of Huanchaco, Trujillo Province, Department La Libertad; in the period between January and February 2013, to determine the effect of the inclusion of three levels of betaine in the diet on the performance of Cobb 500 chickens. A total of 192 male broilers were used in a completely randomized design, distributed in four treatments: T0 without betaine, T1 with 0,05, T2 with 0,10 and T3 with 0,15% of betaine respectively, in the growing and finishing stages. By statistical analysis, the final weights and increases in total weights of the treatments showed highly significant differences (p< 0,01), T3 and T2 treatments had the highest values, 2,79 and 2,75 kg and 2,77 and 2,73 kg respectively, being higher than T1 and T0 : 2,67 and 2,63 kg and 2,66 and 2,62 kg respectively. The feed int...