OBJECTIVE: To determine event free survival (EFS) of children with Wilms tumor (WT) and metastatic liver disease at diagnosis. Summary and Background Data: We reviewed patients with stage IV Wilms tumor treated on National Wilms Tumor Study 4 and 5 to ascertain if they have a worse prognosis than other Stage IV disease. METHODS: A total of 742 patients (pts) with stage IV disease were assessed for EFS (95% confidence interval [CI]) at 5 years after diagnosis. Cohorts included those who underwent resection of the liver lesions compared with those who received only chemotherapy and radiotherapy. RESULTS: A total of 742 patients with stage IV Wilms tumor were enrolled on NWTS-4 and 5, 111 of who had liver metastases. Of these, 96 had favorable histology disease and are the focus of this analysis. Twenty-two patients had a primary liver resection (wedge resection, 18 and lobectomy, 4). After chemotherapy and/or radiation, 13 patients underwent liver resection (wedge resection, 7; lobectomy, 5; and trisegmentectomy, 1). Seventy-one patients (67%) did not undergo surgery for their liver disease. In 14 patients, the liver disease disappeared with chemotherapy only. Eighty-two patients received abdominal radiation. EFS for the patients with metastatic FH Wilms tumor was 75% (95% confidence interval [CI]: (71%, 78%), EFS by Stage IV category was: lung only 76% (95% CI: 72%, 80%) (513 patients); liver, not lung 76% (95% CI: 58%, 87%) (34 patients), liver and lung 70% (95% CI: 57%, 80%) (62 patients), and other sites 64% (95% CI: 42%, 79%) (25 patients). There were no significant differences among stage IV groups (P = 0.60). EFS (95% CI) for the patients with primary resection of the liver metastases (22 patients) was 86% (63%, 95%) compared with 68% (56%, 78%) (P = 0.09) for the 74 with no primary resection of liver metastases. There was no significant difference in EFS for patients with FH Wilms tumor treated with chemotherapy compared with that of patients treated with chemotherapy and radiation (P = 0.63). The EFS (95% CI) for each of the subsets was; no abdominal radiation: 64% (34%, 83%); abdominal radiation, no boost: 77% (55%, 89%); abdominal radiation, boost: 72% (58%, 82%) (P = 0.05). CONCLUSION: Liver metastasis at diagnosis is not an adverse prognostic factor for stage IV metastatic FH WT.