The aim was to evaluate the economic viability of increasing levels of crude glycerin (CG) in diets for finishing lambs. The trial was carried out at Southwest State University of Bahia, Itapetinga-BA. Twenty five crossbred, Santa Inês x Dorper, with 24 ± 2,0 kg, were housed in individual pens. The experimental design was completely randomized with five treatments and five replications. Treatments consisted of increasing levels of dietary CG (0, 2.65, 5.33, 8.06 and 10.84%) and the roughage used was the Tifton 85 hay. Diets were formulated to meet the nutritional requeriments, aiming a gain of 200 g day-1. The analysis was based on use of economic indicators Net Present Value (NPV) and Internal Rate of Return (IRR). The animals dry matter intake decreased linearly (P<0.05) as the glycerin levels increased in the diet. However, there was no effect (P>0.05) on performance and meat production results. None of the treatments showed economic viability.