The usefulness of computerized tomography, lymphangiography and tumor markers has been examined in 20 consecutive patients with pathologic stage I or II nonseminomatous testicular tumors. Computerized tomography had a false negative rate of 40 per cent, a false positive rate of 50 per cent and an over-all accuracy of 69 per cent. Lymphangiography had a false negative rate of 42 per cent, a false positive rate of 0 and an over-all accuracy of 69 per cent. The combination of computerized tomography and lymphangiography did not significantly improve the diagnostic accuracy of either technique alone. Furthermore, because tumor markers usually were elevated in the presence of bulky metastatic disease that was detected easily by either computerized tomography or lymphangiography, they did not add measurably to the sensitivity of either computerized tomography or lymphangiography in the diagnosis of retroperitoneal lymph node metastases. Consequently, retroperitoneal lymphadenectomy remains the only reliable means for accurate staging of patients with nonseminomatous testicular tumors.