1. Nitrogen balance studies were made on eight early weaned calves given diets varying in crude protein content from 11·6% to 22·6% in dry matter.
2. Nitrogen retention increased significantly as the level of crude protein increased to 19·20%; there was no further increase in nitrogen retention when the level of protein was increased to 22·6%.
3. Dry matter digestibility and apparent digestibility of dietary nitrogen rose progressively as the level of crude protein increased.
4. The nitrogen retention of calves fed diets adequate in protein was calculated to be 2·88 g. per 100 g. gain in body weight.