Total pancreatectomy in Alligator mississipiensis (3–4 ft long) produced in 24 hours a rise in blood sugar from the normal average of 73 mg% to 321 mg%, attaining progressively a final value of 606 mg% after 16 weeks. Death in ketosis takes place from 2 to 4 months after the operation. Glucagon, injected intraperitoneally, had its maximal hyperglycemic effect at 24 hours in the control group. The effect persisted for 1 week. In the depancreatized animals the maximal response occurred on the day 8 and the effect persisted for 2 weeks. In the normal animals insulin, injected intraperitoneally, produced a maximum decrease of the blood sugar (from 82 to 16 mg%) in 24 hours. After pancreatectomy the insulin effect was maximal at 96 hours (from 389 to 68 mg%), and the blood sugar values returned to initial levels 10 to 12 days after the injection. Epinephrine hyperglycemia is maximal at 24 hours after intraperitoneal injection in normal alligators and at 5 days in the depancreatized group. In the normal animals after intraperitoneal injection of a glucose load, the blood sugar reached maximal values 8 hours after the injection and approached the initial values only after 5 days. Depancreatized alligators had maximum values at 24 hours and returned to the base line in 7 days. Growth hormone or triamcinolone intraperitoneally injected daily for 1 week produced a mild hyperglycemia in the normal alligators and seveerly impaired the diabetic state of the depancreatized ones, as well as a marked increase in the levels of the ketone bodies.