The size, turnover time and transfer rate of the glucose pool were estimated with glucose–C14 in normal and ketotic cows. The size and turnover time of the pool were both about 1/5 greater in the ketotic than in the normal cows, so that the transfer rate remained similar, being about 1 gm/min. The hypoglycemia which is characteristic of the disease appeared to be associated with an expansion of the glucose space, which in the normal cows approximated the extracellular volume, into the intracellular compartment of the ketotic cows. These results do not favor theories of bovine ketosis which presume a shortage of body glucose. Submitted on June 25, 1959