Crude glycerin is a high energy by-product of biodiesel production. However, some impurities may be present in it including methanol and salts. Methanol can impair liver function.The objectives of this trial were to determine the effects of partial replacement of corn by crude glycerin on growth, hepatic enzymes and carcass characteristics of lambs fed high-concentrate diets. Fifty (40 males and 10 females) White Dorper × Santa Ines lambs were assigned to a randomized complete block design, defined by initial BW, sex and age. Lambs were penned individually and fed, during 56 d (2 periods of 28-d), a TMR composed of 90% concentrate. Diets were isonitrogenous (15.7 ± 0.3% CP, DM basis) and the increasing levels of crude glycerin (83.6% glycerol and 397 mg of methanol/kg, DM basis) were 0, 5, 10, 15 or 20%. Lambs were weighted and blood samples were collected on d-0, d-28 and d-56. Average daily gain (ADG), feed efficiency (FE) and dry matter intake (DMI) were determined in each period. At the end of the 56-d, all ram lambs were slaughtered for carcass characteristics evaluation. Data were analyzed using the MIXED procedure (SAS Inst. Inc.). Orthogonal polynomials for diet responses were determined by linear and quadratic. Replacing corn by crude glycerin did not affect ADG (0.29, 0.29, 0.30, 0.31 and 0.28 kg), DMI (1.03, 1.02, 1.04, 1.08, 1.00 kg/d), FE (0.28, 0.28, 0.29, 0.28, 0.28) and body weight on d-28 (29.3, 29.3, 29.3, 29.2, 28.4 kg) and d-56 (38.9, 38.7, 39.0, 39.2, 38.2 kg). There was a diet and period interaction for DMI. In the second period (d28-d56) a quadratic effect for DMI (1.11, 1.15, 1.18, 1.25, 1.11, kg/d) was observed. Hepatic enzymes (aspartate aminotransferase and gamma glutamyltransferase) activity and carcass characteristics were not affected by crude glycerin addition to the diet. Crude glycerin can be used to replace up to 20% of corn (DM basis) in high-concentrate diet of lambs without detrimental effects on performance, hepatic enzymes and carcass characteristics.