OBJECTIVE: We used a large US clinical cancer registry to assess nodal evaluation performance in children with Wilms' Tumors (WT), to determined factors associated with nodal evaluation, and to define the prognostic importance of nodal status. SUMMARY BACKGROUND DATA: Lymph node assessment remains a part of accurate staging and helps determine therapy for patients with WT. Lack of nodal assessment has been noted but not well studied. METHODS: Patients (0-18 years) with WT from the National Cancer Data Base (1985-2001) were assessed for nodal evaluation. Logistic regression was used to identify factors associated with the likelihood of lymph node evaluation. Survival was estimated using the Kaplan-Meier method. Cox regression was used to estimate the risk of mortality. RESULTS: Of 3593 patients, 1510 (42%) had no lymph nodes evaluated by pathology and reported to the National Cancer Data Base. Of 2083 patients who had lymph nodes assessed, 535 (25.7%) had positive nodes. Patients age 2 years or younger, with larger tumor size, and treated at a higher volume center were more likely to have nodes assessed (P < 0.01). Patients who had nodes evaluated had a better 5-year survival compared with those who did not have nodes evaluated (92.2% vs. 88.1%, P < 0.001). In Cox regression, nodal metastases (P < 0.001; HR: 2.2, CI: 1.6-3.0) were associated with increased risk of death after adjusting for patient, tumor, and hospital characteristics. CONCLUSIONS: Many patients do not have lymph nodes evaluated during WT resection. Opportunities exist for improved staging and possibly survival in patients with WT through better nodal assessment.