An investigation was carried out using 24 adult rams assigned to 4 dietary treatments viz., T1: fed solely on CO-4 variety of hybrid Napier (Napier × Pearl millet) ad lib., T2: CO-4 fodder ad lib. + 150 g crushed maize grain, T3: CO-4 fodder ad lib. + 150 g maize grain + 125 g ground nut cake (GNC) and T4: CO-4 fodder ad lib. + 150 g maize grain + 125 g CSC, to find out the effect of supplementing energy and protein on nutrient utilisation in sheep. The DMI (g/d) was minimum in group T1 and maximum in T3. The DMI/kg W0.75 (g) was higher (P<0.05) in T3 followed by T4, T2 and least in group T1. The DM digestibility was significantly (P<0.05) different among four rations with the highest in group T3 and lowest in T1 and comparable between groups T2 and T4 as well as T3 and T4. The higher (P<0.05) OM digestibility was observed in T3 and T4 than other groups. The CP, EE and CF digestibilities were higher (P<0.05) in sheep fed T3 ration followed by T4, T2 and T1 rations. The lowest NFE digestibility was observed in animals fed T1 ration with no difference among T2, T3 and T4 groups. The NDF digestibility was higher (P<0.05) in T3 and T4 and ADF digestibility was higher (P<0.05) in group T3. Hemicellulose digestibility was comparable while cellulose digestibility was lower (P<0.05) in group T1 than other groups. It was concluded that the digestibility of nutrients in CO-4 fodder supplemented with groundnut cake was better and addition of protein and energy sources are essential to provide adequate nutrients required in the rations of sheep.