IN AN earlier study of the effect of daily glucagon administration on rats and rabbits, the most interesting result was a large increase in the concentration of liver glycogen in both species (1). This paper reports the results of experiments designed to study further the increased concentration of liver glycogen produced by daily glucagon administration. Helmer and Root (2) have suggested that the response of the blood sugar to glucagon administration is dependent upon the amount of liver glycogen available. Chronic daily administration of glucagon should bring about an increased response to a given dose of glucagon if there is a correlation between liver glycogen stores and glucagon response. Such an increase was found to occur in rabbits treated twice daily with glucagon for a period of 3 months.