A review of the imaging studies of five children with Wilms tumor and nephroblastomatosis demonstrated that contrast-enhanced computed tomography (CT) can show the multifocal involvement of nephroblastomatosis more accurately than either excretory urography or real-time ultrasound (US). In all five children, CT demonstrated multiple areas of nephroblastomatosis along the renal cortex. US showed a single intrarenal mass in each child (one bilaterally) but did not show the cortical nephroblastomatosis. Excretory urography also demonstrated only the dominant mass of the Wilms tumor. The superiority of CT is attributed to better spatial resolution and soft-tissue contrast differentiation and clear demarcation between nonenhanced nephroblastomatosis and enhanced normal renal parenchyma. Contrast-enhanced CT is therefore recommended for the evaluation of clinically abnormal and contralateral kidneys in all children with suspected Wilms tumor.