In this prospective study 45 patients with cervical lymphadenopathy treated by operation, radiation and/or chemotherapy were examined by color-duplex sonography. The aim was to investigate the lymph node perfusion and to find out whether differentiation between benign and malignant nodal disease after therapy was possible by resistance and pulsatility indices. In 200 of 245 lymph nodes (82%) color-duplex sonography was able to detect perfusion. Using a pulsatility index (PI) threshold of 1.6 and resistance index (RI) threshold of 0.8, differentiation between reactive nodal enlargement and metastases was possible with an accuracy of 96%. Differentiation between lymphomas and metastases by RI and PI was not possible. Qualitative assessment of perfusional patterns was useful in detecting malignancy because reactively enlarged nodes showed greater hilar perfusion whereas metastases showed an increased peripheral perfusion. Lymphomas had both increased central and peripheral perfusions.