To analyze changes in the overall survival (OS) rate of children with Wilms tumor treated in a single institute over nearly 30 years. This study included 327 children with a newly diagnosed Wilms tumor. Their median age was 3 years, and the male:female ratio was 1.1. Survival rates were analyzed according to the stage of disease, histopathology, and different treatment regimens used between 1972 and 1999. At diagnosis, 51.1% of patients had advanced stage disease. Ten patients had anaplasia, and; 97% (317 patients) of the tumors had favorable histopathology. The 10-year OS rate was 60.6% for the entire group, but varied according to the years in which the patients were treated, the chemotherapy regimen, and stage of disease. Patients treated during the periods of 1972 to 1979, 1980 to 1989, and 1990 to 1999 had 10-year OS rates of 48.5%, 64.3%, and 72.8%, respectively. The 10-year OS rate in children treated with actinomycin only was 36.7% compared with 48% for children treated with the actinomycin-D+vincristine regimen with a 3-month interval, 67% for the actinomycin-D+vincristine regimen with a 1.5-month interval, 54.5% for the poor-risk regimen (actinomycin-D, vincristine, cyclophosphamide, and adriamycin), and 53.4% for the SIOP-9 protocol. Children with stage I to IV disease had 10-year OS rates of 75%, 77.1%, 54.4%, and 30.4%, respectively. The 10-year OS rates for children with stage III and IV disease increased from 46.4% and 13.4% for patients treated between 1972 to 1979 period to 75% and 54.5% for children treated during 1990 to 1999. The 10-year OS rate for children with Wilms tumor improved as treatment strategies evolved, illustrating that pediatric oncology in Turkey is developing parallel to the Western world.