The objective of this study was to evaluate the effect of supplementation of varying levels of cassava root meal (CRM, 300 and 1,000 g), without or with 700 g groundnut cake (GNC) on intake and performance of growing Laisind cattle fed with a basal diet of urea-treated rice straw (URTRS). Twenty-four male cattle of crossbred Laisind (50% Red Sindhi and 50 % local Yellow, both Bos indicus), from 15 to 17 months of age, 165-175 kg body weight, were used. They were assigned to a completely randomized block design in a 2 × 2 factorial arrangement (two CRM levels and two GNC levels). Intake of URTRS (interaction, P < 0.01) and digestibility of neutral detergent fiber (interaction, P < 0.05) decreased as CRM level increased on the diets without GNC but was not affected by CRM level on the diets with GNC. The total dry matter intake (interaction, P < 0.05) and live weight gain (LWG) (interaction, P < 0.001) increased as CRM level increased on the diets with GNC, but no difference was observed on the diets without GNC. In conclusion, supplementation of 1,000 g CRM should be in combination with 700 g GNC to avoid the negative effects on URTRS intake and digestibility, therefore improving LWG of growing Laisind cattle fed on a URTRS-based diet.