In a previous publication, we described a Doppler ultrasound method for diagnosing venous disease of the lower extremities.1 This technique is used to detect occlusion of deep veins due to thrombosis and incompetent valves associated with the postphlebitic syndrome. The preliminary results in 72 patients with confirmed diagnoses indicated that the ultrasound method was significantly more precise than clinical appraisal alone in the diagnosis of thrombotic occlusion of deep veins of the lower extremities.2 We have expanded this series by adding 75 more patients in whom confirmation of Doppler ultrasound findings was obtained usually by venography and occasionally by operation or autopsy. As our experience has increased, we have simplified the examination for occlusion by deleting certain maneuvers which were found to be redundant. This has enabled us to evolve a more systematic and specific set of criteria for abnormality on the ultrasound examination. Furthermore, the additional clinical