PURPOSE: We determined the frequency of and risk factors for congestive heart failure following treatment for Wilms’ tumor that included doxorubicin. PATIENTS AND METHODS: Flow sheets and medical records were reviewed to identify cases of congestive heart failure in a cohort of patients treated on National Wilms’ Tumor Studies (NWTS)-1, -2, -3, and -4. The frequency of congestive heart failure was estimated using the Kaplan-Meier method. A case-control study was conducted to determine the relationship among cumulative doxorubicin dose, site(s), total dose of abdominal and thoracic irradiation, sex, and the frequency of congestive heart failure. RESULTS: The cumulative frequency of congestive heart failure was 4.4% at 20 years after diagnosis among patients treated initially with doxorubicin and 17.4% at 20 years after diagnosis among those treated with doxorubicin for their first or subsequent relapse of Wilms’ tumor. The relative risk (RR) of congestive heart failure was increased in females (RR = 4.5; P =.004) and by cumulative doxorubicin dose (RR = 3.3/100 mg/m(2); P <.001), lung irradiation (RR = 1.6/10 Gy; P =.037), and left abdominal irradiation (RR = 1.8/10 Gy; P =.013). CONCLUSION: We conclude that congestive heart failure is a risk of treatment with doxorubicin for Wilms' tumor. Additional follow-up of those children treated on NWTS-4 will be necessary to determine if the decrease in dose to 150 mg/m(2) significantly reduces this risk.