varicose veins are present in up to 40% of the population. They may be associated with considerable morbidity. Around 70% of patients with chronic venous insufficiency have evidence of superficial venous incompetence on duplex imaging.in this publication we review the evidence available regarding the pathogenesis of varicose veins.a number of theories have been suggested. The present data suggests that abnormalities in the venous endothelium and smooth muscle cells result in vein wall dilatation with secondary valvular incompetence. However, there is also evidence to support acquired venous valve failure. Congenital venous valve abnormalities have not been well studied.further work is required on this relatively neglected topic. The use of improved imaging such as high-resolution ultrasound is likely to significantly improve our understanding of venous valve function and pathology.