We encountered three patients with pediatric systemic sclerosis. Patient 1 had systemic scleroderma, pigmentation and interstitial pneumonia at the age of 10 years. Nine months after disease onset, she was treated with intravenous cyclophosphamide pulse therapy as induction therapy. After the initial treatment, the following clinical manifestations were dramatically improved: interstitial pneumonia, scleroderma and total skin score. Patient 2 was a 7-year-old girl, who complained of systemic scleroderma and pigmentation, and was found to have pulmonary hypertension. Six months after disease onset, she was administrated intravenous cyclophosphamide pulse therapy. Her scleroderma and total skin score were improved and the pulmonary hypertension did not deteriorate. Patient 3 was a 15-year-old girl. Her initial treatment was vitamin E alone. She was admitted to our hospital two and half years after disease onset. Although she was given immunosuppressive therapy including cyclophosphamide, the severe condition of persisted, and she died after five months. It became possible for patient 1 and 2 to achieve and maintain a marked improvement of the clinical manifestations as a result of cyclophosphamide pulse therapy early in the course of the disease. We further observed that their total skin score was decreasing while the clinical manifestations improved.