This study was carried out to evaluate the influence of diets supplemented with glycerin as an alternative ingredient to corn on the performance and carcass characteristics of Santa Inês confined lambs. The study involved 27 lambs aged 90 days, having an average initial weight of 26.33 ± 0.15 kg. Lambs were randomly distributed into a control group and groups with diets containing 15 and 30% glycerin in the total feed. Diet was formulated with 40% roughage and 60% concentrate. The experimental design was completely randomized, and the production performance and carcass characteristics were analyzed by analysis of variance, and the subjective carcass characteristics, by general linear models. The daily average gain was 0.21, 0.24 and 0.23 kg/day; feeding conversion was 6.39, 5.73 and 5.92 kg of diet/kg BW for control animals, and those fed with 15 or 30% glycerin, respectively, without treatment differences. Lambs were slaughtered, weighing 34 to 36 kg, and average weight of the cold carcass and commercial carcass yield were evaluated. The results were, respectively, 15.97 kg and 49.18%, for control, 15.96 kg and 48.31% for animals fed with 15% glycerin, and 15.79 kg and 47.87% for those treated with 30% glycerin, with no treatment effects. Meat tenderness and cooking loss averages were not affected by diets, with 5.07 kg and 40.45%, 5.10 kg and 40.81%, and 5.27 kg and 39.04%, respectively, for control, and those fed with 15 or 30% glycerin. Therefore, it is possible to conclude that up to 30% of medium purity glycerin in the dry matter of the diet can be used to replace corn, without any negative effect on lamb performance or carcass characteristics.