Background: Wilms’ Tumor (nephroblastoma) is the most common renal malignancy of childhood. The aim of the study was to evaluate the characteristics of Wilms’ Tumor and the results of combined modality treatment obtained in our center in Tehran. Methods: Fifty-five patients diagnosed as having Wilms’ Tumor were studied in the period between February 1992 and March 2002. Demographic features, mode of presentation, associated anomalies, the stage of Tumor, histopathologic results, and the survival rates were evaluated.Results: Of these 55 patients, 31 were males and 24 were females (M/F = 1.2). The mean age at the time of diagnosis was 45.2 months. The distribution of 54 operated patients according to the surgical stage was: stage I 32.7%, stage II 16.36%, stage III 38.1%, stage IV 9%, and stage V 1.8% (one patient (1.8%) has not been operated).Favorable histology was diagnosed in 54.5% and unfavorable histology in 43.6% of the patients. The patients were treated according to National Wilms’ Tumor Study protocols. The relapse-free and overall 4 years survival rates were 71% and 86%, respectively.Conclusion: As a developing country, with similar relapse free and overall survival rates to National Wilms’ Tumor Study, our institution showed an improvement in the treatment of patients with Wilms’ Tumor in recent 10 years, but with more adaptation to the National Wilms’ Tumor Study treatment protocols better optimum results seem to be achievable.