The diagnosis of renal glycosuria is based on the syndrome of (1) glycosuria without hyperglycemia, (2) glucose excretion almost entirely independent of carbohydrate intake, and (3) absence of diabetic symptoms. To these data should be added, I think, a fourth, namely, that such patients do not subsequently develop diabetes mellitus or show a disturbance of carbohydrate metabolism similar to that found in diabetes mellitus. Not many reported cases have been observed long enough to answer either of the latter two questions. Garrod's1 case was observed six years, Goto's2 five years. Allen, Wishart and Smith3 have recently recorded three cases of renal glycosuria, and have discussed the unsatisfactory nature of this interesting anomaly. It is the purpose of this paper to place on record four cases, patients who have been under observation for from two to eight years since the onset of the disease and on two of whom late metabolic