Radionuclide venography was performed in patients who were suspected clinically to have thromboembolic disease of the lower extremities and/or pelvis. A moderately large volume of pertechnetate was administered in the dorsal vein of each foot without the benefit of applied tourniquets at the time of injection. Sixty-five (27.2%) of 242 studies were abnormal; the majority revealed defect(s) and collaterals, some collaterals only, and a few defects only. In 140 normal patients only the deep venous system was outlined in 74.5%, while the remainder defined one or both sides of the superficial venous system (great saphenous vein). The merits and apparent advantages derived from radionuclide venographic procedure are discussed. The method is simple, reproducible, and useful in assessing thromboembolic disease, particularly in the deep venous system of the lower extremities and pelvis.