A new technique to obtain biopsy specimens from the pelvic lymph nodes is presented. A mediastinoscope introduced through a small incision in the abdominal wall allows the identification of the pelvic nodes. A series of 12 patients with prostatic or bladder carcinoma is presented and the feasibility of the method is documented. There was no morbidity associated with the endoscopic node biopsy. Suggestions for modification of the instrument are made. The method is now under further scrutiny to establish its place among other available methods to study lymphogenous spread of pelvic malignancies.