Thirty-six patients with advanced seminoma treated with cisplatin combination chemotherapy were evaluated to assess the significance of postchemotherapy residual radiographic mass. All patients had a minimum follow-up of 2 years. Of the 36 patients 21 had an evaluable residual radiographic mass after completion of chemotherapy. Twelve of these patients had a less than 3 cm maximal transverse diameter residual mass, and nine had a greater than 3 cm persistent mass postchemotherapy. Only three of these 21 patients underwent postchemotherapy retroperitoneal lymph node dissection, and the histopathology revealed only necrotic fibrous tissue. The remaining patients were followed by close observation including repeat abdominal computed tomography (CT) every 3 months the first year and every 6 months the second year (or until normal); further therapeutic intervention was given only on evidence of progressive disease. Nineteen of these 21 patients have no evidence of disease, including eight of nine with greater than 3 cm persistent radiographic abnormality. The optimal management for advanced seminoma patients with a persistent radiographic mass postchemotherapy remains unresolved. However, based on this small series, we feel that observation is a viable option, reserving radiotherapy or chemotherapy for those patients who subsequently develop progressive disease.