Pathologically enlarged lymph nodes have been examined with a commercially available 10 MHz continuous-wave Doppler flowmeter. Many enlarged lymph nodes gave rise to significant Doppler-shift signals indicating increased blood flow. The signals have been spectrum analysed and the large diastolic flow components suggest that there is considerable arterio-venous shunting within lymph glands involved in leukemia, lymphoma and carcinoma. It also seems that the signals tend to diminish in response to treatment. The Doppler signals have been used in an imaging system to produce a vascular map of the region of the enlarged gland. It is suggested that these findings might be applicable to the detection of neoplastic tissues in less accessible sites.