The ultrasound investigation in patients with chronic venous disease (CVD) is very different from examinations to rule out deep vein thrombosis. Most examination for CVD are for diagnosis and planning for treatment of venous insufficiency and has to be done with the patient on standing position and not laying down. If it is done laying down gravity will not be present on the valvular structures of the veins and a lot of information about the valve functions will be missed. The information gathered by the duplex investigation has a significant impact on what type of treatment will be most appropriate and therefore recommended. Failure to identify and treat all sources of reflux may result in outright treatment failure. Duplex ultrasound is essential to the performance of endovenous ablative procedures including endovenous laser, radiofrequency occlusion, and ultrasound guided sclerotherapy. The examination will be also used for outcome assessment after treatment. The doctors performing these procedures need to be familiar with the venous anatomy and physiology. One way to know if your doctor is proficient on this field is asking if there are Registered Phlebology sonographers (RPhS) or a Registered Vascular Technologist (RVT).