Steroid Resistant Nephrotic Syndrome(SRNS) in children has poor prognosis and no effective therapy. In 1994, Ravi Elhence have reported that IV cyclophosphamide therapy was effective against SRNS of children. So, we evaluated the efficacy of IV cyclophosphamide in 3 children with biopsy proven steroid-resistant MCNS. And the result was the rapeutic failure. In conclusion, IV cyclophosphamide therapy wass not effective against SRNS of children.