The aim of the study was to determine the effect of feeding feed blocks containing varying proportion of urea-treated paddy straw (UTPS) on dry matter (DM) intake (DMI), nutrient utilization and N balance in Mithun. For the purpose, four adult male Mithun (279.5 ± 8.2 kg) were selected and offered four experimental rations viz. R(1) (Napier fodder + concentrate at 60:40), R(2) (UTPS + concentrate at 50:50), R(3) (UTPS + concentrate at 60:40) and R(4) (UTPS + concentrate at 70:30) in 4 × 4 Latin square design. The DMI % of body weight was 2.59, 2.96, 2.85 and 2.77 and the DMI g kg(-1) W(0.75) was 107, 123, 118 and 115 in Mithun fed R(1), R(2), R(3) and R(4), respectively. The mean DMI was (P < 0.01) higher in animals fed R(2) and R(3) than R(1) and R(4), whereas the water intake was (P < 0.01) higher in Mithun fed R(2), R(3) and R(4) than R(1). The digestibility of DM, organic matter, crude protein, crude fibre, neutral detergent fibre and cellulose were (P < 0.05) higher in animals fed R(2), R(3) and R(4) than R(1). A positive N balance was observed in all the experimental animals, with higher (P < 0.05) values among the animals offered R(2), R(3) and R(4) than R(1). The digestible crude protein and total digestible nutrient intakes were higher (P < 0.05) in Mithun fed R(2) and R(3) than R(1) and R(4). It is concluded that the UTPS can be incorporated up to 70% to formulate the complete feed/feed block and can be used for feeding of Mithun under complete confinement system.