From l988, the use of preoperative chemotherapy for selected Wilms tumor was adopted at Yonsei Cancer Center. Between 1988 and 1992, 10 children has given preoperative chemotherapy. During that period, 21 children with Wilms tumor underwent primary nephrectomy(postop- erative treatment group). The criteria for preoperative chemotherapy were (a) initial surgical removal is excessively hazardous to patient (b) inoperable because of large size or extent of disease (c) patient with vena cava or atrial extension (d) radiologic evidence of extensive local invasion of adjacent or- gans or distant metastasis. After preaperative treatment, the tumor size was markedly(>50%) reduced in five patients. In all patients, nephrectomy was performed safely without rupture of tumor. Except stage IV patients, the dawnstaging may reduced the use of radiotherapy during ad)uvant treatment. The 3-year survival rate for patients with preoperative chemotherapy was 80%. The survival of the preoperative chemotherapy group was similar to that in the postoperative treatment group(2-year survival rate; 80% vs 84%). But there was a higher rate of local recurrence in preoperative chemotherapy group. We conclude that preoperative chemotherapy is the effective method of treatment in the selected cases of Wilms tumor.