This study was carried out to study changes of proteinuria in patients with primary corticosteroid-resistant nephrotic syndrome in Uro-Nephrology departement of the National Hospital of Pediatrics from 01/01/2008 to 31/12/2010. The results showed that proteinuria of primary corticosteroid-resistant nephrotic syndrome patients at the beginning was higher than primary corticosteroid-sensitive nephrotic syndrome with p 0.05. After 10 days 'of treatment, proteinuria of primary corticosteroid-resistant nephrotic syndrom'e patients was' decreased less than patients with primary corticosteroid-sensitive nephrotic syndrome with p 0.01. Patients with primary corticosteroid-resistant nephrotic syndrome with renal failure or/and hematuria, their average proteinuria was highest. Average proteinuria after 1 month of treatment with cyclophosphamide was decreased to compare with before treatment (p 0.01). Average.time to proteinuria negative after treatment with cyclosporine A ana Mycophenolat mofetil was the shortest, at nearly 2 months. In conclusion, the average proteinuria in patients with primary corticosteroid-resistant nephrotic syndrome was almost unresponsive to bolus Prednisolon but it responsed with cyclosporin A and Mycophenolat mofetil with the average time of 2 months.