1. The maintenance crude protein (CP) requirements of subadult nilgai antelope (Boselaphus tragocamelus) were determined by nitrogen balance. Four isocaloric pelleted diets, ranging from 8.4 to 23.8% CP, were fed. 2. Subadults maintained a positive nitrogen balance on all diets. Linear regression showed that 95.8% of diet CP was truly digested and estimated metabolic fecal nitrogen (NFN) excretion at 0.388 gN/W0.75/day. 3. Estimates for endogenous urinary nitrogen excretion and maintenance nitrogen requirement, derived through linear regression, were erroneous. Consequently, the former was calculated based on metabolic size (0.126 gN/W0.75/day) and added to MFN to obtain an 0.514 gN/W0.75/day estimate of required nitrogen for maintenance. This value is between the levels recommended for maintenance of yearling deer and cattle. 4. Given the same level of dry matter intake (68.6 g/W0.75/day) and true CP digestibility, study animals would be able to meet N equilibrium on a 4.89% CP (dry matter basis) diet. 5. Based on data from other sources, natural diets containing 6.98% CP would need to be consumed by free-ranging subadults to maintain body weight.