The ultrasound appearances of three children presenting with virilization are described. All cases were also examined by computed tomography. The value of ultrasound in the initial detection of virilizing neoplasm and in follow-up studies for localization of tumor recurrence following initial surgery are outlined. The advantages of ultrasound include confirmation of extrarenal and extrahepatic location in longitudinal sections, and clear demonstration of invasion of hepatic veins, the inferior vena cava (IVC), and the right atrium on real-time scanning. Computed tomography is also useful, particularly in the localization of small lesions and the detection of pulmonary metastases.