Ten Thai native × Lowline Angus crossbred (50:50) steers were used in a completely randomized design to receive two treatments including concentrate containing cassava chips (Control) and fermented cassava starch residue (FCSR) as major carbohydrate sources. FCSR was prepared as yeast (Saccharomyces cerevisiae) inoculates with exogenous enzyme addition. All steers received ad libitum rice straw and concentrate in equal proportions (1:1). Replacement of cassava chip with FCSR increased neutral detergent fiber and acid detergent fiber intakes but decreased non-protein nitrogen intake of steers. Digestibility of dry matter, organic matter, and crude protein were decreased with replacement of cassava chip by FCSR; however, digested nutrients were similar between groups. Replacement of cassava chip in the concentrate with FCSR resulted in comparable growth performance and feed efficiency of the feedlot steers. Moreover, carcass characteristics in terms of yield and meat quality of the steers were not affected by cassava chips replaced by FCSR as a major carbohydrate source in the concentrate. In conclusion, replacement of cassava chip in the concentrate with FCSR decreased feed digestibility; however, it did not impact negatively on growth performance and carcass traits of feedlot Thai native × Lowline Angus crossbred steers.