The objective of this study was to evaluate the efficacy of replacing oat hay with coffee husk for the feeding of confined lambs. In this study, 24 male Texel lambs of approximately 60 days of age and with a mean ± standard error weight of 21.95 ± 5.81 kg were examined. Their diet was composed of 30% oat hay and 70% concentrated feed per kilogram of dry matter. The experimental design was randomized and included four treatments (0, 7.5, 15, and 22.5% of coffee husk in the total dry matter), with six replicates of each treatment. The animals were slaughtered when they reached a mean live weight of 32 kg. There was no significant difference in dry matter intake and mean daily weight gain (which were 197 g day-1) among treatments. The mean daily weight gain (DWG) was not significantly affected (P > 0.05) by the replacement of oat hay with coffee husk in the diet, with the overall mean DWG being 215.05 g day-1. There were no significant differences (P > 0.05) among treatments in any of the studied carcass variables, and the mean true carcass yield was 53.9%. The lambs presented a mean finishing score of 2.96 (on a scale of 1 to 5) and a conformation of 4.21 (on a scale of 1 to 6), characterizing them as good carcasses. In terms of economic viability, the 7.5% diet stood out as the one that had the highest profitability, generating a profit of $ 3.25 USD per kg of carcass produced. Coffee husk can therefore replace oat hay in the feed of finishing lambs in concentrations of 0.075 to 0.225 kg kg-¹ of total dry matter with biological and economical efficacy and generating good commercial carcasses.