Two cases of congenital nephrotic syndrome (C.N.S.) with a prolonged survival are related. The AA. outline some clinical and immunological features which are already known but not currently employed to therapeutic ends. Probably due to metabolic disorders, the biological and clinical hypothyroidism is a prominent problem which worsens either poor skeleton maturation or neurological development of these patients; adequate doses of thyroid hormone produced a marked increase of the muscular tone, skeleton maturation and neuropsychological development in both patients. Periodic plasma administration (2-3 times monthly) during the first year of life, and a great care to avoid all extra-family contacts and infections in the same period, resulted to be the prevalent reason of the prolonged survival of these children (the plasma acting as a source of proteins and immunoglobulins). The immunologic assessment demonstrated in both children as marked depression of T-cells number and function, besides a hypogammaglobulinemia. This aspect of the immunocompetent system is similar in C.N.S. and nephrotic syndrome of the aged children and perhaps could approach the pathogenesis of the two diseases. The cases related demonstrate that a better assistance is possible and necessary in order to obtain the longest survival of these patients and therefore the best results in dialitic treatment and in transplantation programs.