Between 1920 and 1932, approximately 160 patients more than 15 years of age, who presented the "nephrotic syndrome" prominently have been carefully studied at the Mayo Clinic; that is, the patients displayed marked edema, profuse albuminuria, elevation of the values for blood lipoid and a decrease in the value for serum proteins. Many patients have been admitted more than once, and the subsequent course of most of the patients has been traced. In thirty cases, a clinical diagnosis of lipoid nephrosis was justified on the first admission according to the strict criteria for diagnosis of this disorder, but in seven of these cases subsequent examinations have shown the development of definite, chronic glomerular nephritis, four patients having died in uremia. Nineteen cases corresponded to the so-called "mixed nephrosis" that has been referred to in the literature. As a matter of fact, some of the cases that have been reported as