The history of Doppler ultrasound in peripheral vascular diagnosis is considered in terms of basic developments, clinical applications and impact on medical practice. Many early developments occurred at Osaka University in Japan and the University of Washington in the United States. Through progressive steps, Doppler ultrasound technology has provided clinical applications in blood-flow sensing, waveform analysis, localizing blood flow and two-dimensional (2-D) mapping of blood flow. An important advance was the development of duplex and color Doppler scanning. Real time velocity measurements and flow mapping have led to many clinical applications. Two important applications have been detection and grading of atherosclerotic plaques in the internal carotid artery and the diagnosis of deep venous thrombosis. Doppler ultrasound is the preferred noninvasive imaging method for each of these clinical problems. The recent reaffirmation of carotid endarterectomy as the appropriate management for certain categories of carotid atherosclerotic occlusive disease has led to guidelines for selecting patients for carotid endarterectomy. New Doppler ultrasound criteria are being developed to identify categories of stenosis that relate to these guidelines. The establishment of Doppler ultrasound has led to training programs for technologists and physicians, certification of technologists and establishment of standards and quality control measures for vascular laboratories.