There were 340 episodes of severe diabetic ketoacidosis in 257 patients, July 1, 1965 to June 30, 1968. Fatality in thirty-two cases was associated with significantly elevated admission serum glucose, urea nitrogen, osmolality and age. Major associated causes of death were infection and myocardial infarction. Twenty episodes of acute pancreatitis, with only two deaths, demonstrated severe morbidity and marked elevation of serumglucose and urea nitrogen. Fourteen of the twenty occurred in alcoholics. There were eleven episodes in ten pregnant women, with one maternal and seven fetal deaths. Admission serum potassium, recorded in 336 episodes, was markedly elevated in 22 per cent and decreased in 4 per cent. Including all multiple admissions, there were 482 episodes; forty had hypoglycemic reactions, none with fatality or severe morbidity. Nine cases of nonketotic hyperosmolar coma, with five deaths, demonstrated very high admission serum glucose, urea nitrogen, and osmolality levels.