Abstract 1. 1. Adult pocket gophers, fed diets of natural vegetation in the laboratory during summer and winter, remained in positive N balance in all feeding trials. 2. 2. Nitrogen budgets for free-ranging pocket gophers were calculated and revealed that total N influx exceeded 2400 mg N·dkg −1 day −1 in summer and 2300mg N·kg −1day −1 in winter. 3. 3. Apparent N assimilation was 50 and 53% in summer and winter, respectively, and truly digestible N requirements were ⋍ 680 mg N·kg −1 day −1. 4. 4. These budgets indicate that, in spite of seasonally-changing quality of available forage, pocket gophers remain in positive N balance, due largely to shifts in forage preference with season.