Bilateral pedal lymphangiography was performed in the staging of 208 patients with prostatic carcinoma. Forty-seven (23%) were found to have lymph node involvement, and 40 of these 47 had Stage C disease. Nine per cent of the Stage C1 patients (moderately advanced disease) and 37% of Stage C2 (massive carcinoma) had lymph node metastases. The distribution of the abnormal nodes was in continuity with the lymph node drainage from the prostate. The external iliac nodes were the most frequent site of metastases. Histological confirmation was obtained in 20 of the 40 positive Stage C2 cases. More recently, percutaneous aspiration biopsy of the opacified nodes was used to document the presence of metastic disease, thereby extending the value of lymphangiography.