Minimal glomerular changes were found in 80% of the cases of nephrotic sindromes in children. 5 groups can be separated under light microscopy. Electron microscopy always shows foot processes fusion. 80% of the children show edema, one third has transient hematuria, proteinuria is selective for small molecules, plasma B 1 C globuline levels are normal. According with the International Study of kidney disease in children, prednisone therapy gives positive results in 84% of all cases (Early responders) but many of them relapse (Frequent relapsers); the long-term prognosis with steroid is poor in the majority of cases. Cyclophosphamide therapy (2,5-3 mg/kg/die for 6 week and for a maximum of 60-80 days) gives better results and lesser relapses, but caution is needed because of an higher toxicity.