Sheep farming is designated to economic exploitation, and dry matter intake is the most important factor that influences the performance of animal, thus seeking alternative foods. This study aimed to evaluate the effects of inclusion levels of cassava peel on intake, digestibility and performance of feedlot lambs. We used 32 crossbred lambs Santa Inês uncastrated, mean body weight of 21 ± 1.5 kg. Treatments were arranged in a randomized design to animals, with inclusion levels of cassava peel (0, 10, 20, 30%) in the diet dry matter and forage cassava leaf hay. During 70 days, there have been weighing the food provided, leftovers, and animals, and feces collection. The intake of dry matter (DMI), organic matter (OMI), crude protein (CPI), ether extract (EEI), neutral detergent fiber corrected for ash and protein (NDIap), total carbohydrates (CTI), non-fiber carbohydrates (NFCI), total digestible nutrients (TDNI), as well as DMI and NDFap/kgCP, DMI and NDFIap/PC0.75 levels have not been affected by the inclusion of cassava peel. Similar results for DM digestibility, NDF, CP, MO, CT and the TDN. DEE had a growing linear effect whereas DNFC presented a quadratic effect. Average daily gain (ADG), feed conversion (FC), initial body weight (BWinitial), final body weight (BWfinal), warm carcass weight (WCW) and warm carcass yield (WCR) showed no changes. It is concluded that the peel cassava may be included in diet until 30%, without change dry matter intake and animal performance.