This work aims to provide an understanding of the principles and practice of vascular ultrasound. Some of the basic theory behind the science and instrumentation of ultrasound is considered to help in understanding the function of scanner controls, and enabling the reader to obtain optimal images and Doppler recordings. Specific disorders of the arterial and venous systems are covered and the techniques for diagnosing these problems described. Examples of normal and abnormal images and Doppler recordings are included and the interpretation of these discussed. To conclude, some aspects of providing a vascular ultrasound service are examined.