Effects of dietary arginine levels of 1.2%, 1.7% and 2.2% of dry matter (DM) (4.8 g/16 g N, 6.4 g/16 g N and 8.0 g/16 g N, respectively) and excess dietary lysine (6.5% in DM, 22 g/16 g N) were investigated in male mink kits fed low‐protein diets supplemented with a mixture of amino acids in the growing period during 4 weeks in July‐August. Urinary excretion of orotic acid, growth performance, feed consumption, plasma concentrations of ammonia (NH3), orotic acid, urea and glucose were studied. The results showed that arginine is an essential nutrient for mink kits in the growing period and that excess dietary lysine antagonizes arginine. An arginine supply of 2.2% of DM (8.0 g/16 g N) resulted in minimum urinary excretion of orotic acid and a supply of 1.7% of DM (6.4 g/16 g N) prevented increased plasma concentrations of NH3. Growth performance was negatively affected by the low protein level in all diets. The plasma concentrations of orotic acid, urea and glucose were not affected by the dietary levels of arginine.