An experiment was conducted to the effects of increasing levels of crude glycerin (0, 6, 12 and 18%) used as a substitute for corn in lamb feed on the quantitative characteristics of the carcass. A total of 40 crossbred Santa Inês lambs that were four months old with a mean initial weight of 21.0 ± 0.8 kg were randomly distributed in four treatments with ten replicates. The animals were slaughtered after 66 days of confinement. The effects of crude glycerin as a replacement for corn in the diet of the lambs on the carcass characteristics, commercial cut weight and yield and carcass measurements were studied. There was an increasing linear effect for body weight at slaughter with the replacement of corn by crude glycerin. The dry matter (DM) and metabolizable energy (ME) intakes, weight of the empty body, hot carcass weight and cold carcass weight showed a quadratic effect, with maximum crude glycerin levels estimated at 10.9, 9.8, 10.83, 11.78 and 11.35%, respectively. The initial pH was not influenced by the substitution of corn for crude glycerin, while the final pH presented a quadratic effect. The other parameters of the carcass and the weights and yields of commercial cuts were not influenced. There was also no effect of the diets on carcass morphometric measurements, except for the thoracic perimeter and the carcass compactness index, which presented quadratic and linear effects, respectively. Crude glycerin can replace up to 18% of corn because favour the muscle tissue deposition without promoting changes in the main carcass characteristics of lambs.