We investigated whether non-contrast three-dimensional computed tomography-venography (3DCTV) using 128-row multidetector computed tomography (MDCT) could be the first-choice diagnostic imaging modality for the treatment of varicose veins. Its utility was assessed in terms of estimation of the venous function, ability to visualize incompetent perforators, association with deep venous diseases, and determination of surgical procedures in 1348 patients with 2696 limbs who underwent non-contrast 3DCTV between September 2009 and August 2013.A positive correlation was observed between the diameter of the great saphenous vein and the venous filling index (r = 0.539). The detection rate of incompetent perforators was 86.7%. In deep venous incompetence and deep venous thrombosis, a characteristic finding showing a wide net-like spread of varicose veins from a branch not communicating with the saphenous vein was observed. Non-contrast 3DCTV facilitated an objective understanding of the overall three-dimensional images of varices and was useful for determining surgical strategies. Although the concomitant use of duplex scan is necessary for assessment depending on the situation, it appears that non-contrast 3DCTV could be the first-choice diagnostic imaging modality. (This article is a translation of Jpn J Phlebol 2014; 25: 332-9.)