To evaluate the usefulness of regular radiographic screening to detect an asymptomatic intraabdominal tumor in patients with an increased risk of developing Wilms tumor, we reviewed the files of patients with hemihypertrophy, aniridia, or Beckwith-Wiedemann syndrome who were registered on the National Wilms Tumor Studies. Screening was employed infrequently in the management of children with hemihypertrophy, with only 25% (6/24) of those whose hemihypertrophy was identified more than 30 days prior to the diagnosis of Wilms tumor undergoing such examinations. Most patients with aniridia were evaluated regularly for the occurrence of Wilms tumor. There were more stage 1 tumors identified in patients whose tumor was detected only through radiographic evaluation. The role of routine radiographic screening needs to be carefully evaluated in a homogeneous group of patients such as those with aniridia using a prospective study design to determine if such screening improves the survival rate of children with this rapidly growing, but readily treatable form of childhood cancer.