Abstract. Nephrocalcinosis and renal insufficiency in a case of vitamin D intoxication are described in order to emphasize the risk of overdosage in careless or uncontrolled administration of vitamin D, and to report a successful form of treatment in which sodium phytate may have played an important part. The case indicates that it may be possible to reduce the serum calcium level by oral administration of sodium phytate, and that—with the patient at home—this level can be kept low for a long time by means of a low calcium diet. It is also indicated that a distinct roentgenologic regression of calcification of the renal tissue, with simultaneous improvement of renal function, is quite possible.