Perforator incompetence is an important part of assessment of chronic venous insufficiency (CVI), but the criteria for perforator incompetence and the relationship with clinical severity is not well established. AIM: To study whether measurement of diameter of perforator correlates with clinical severity of venous insufficiency. MATERIALS AND METHODS: One hundred and forty five consecutive patients (168 limbs) with varicose veins were evaluated with Doppler study of lower limb veins. Clinical severity and diameter of perforators were assessed. RESULTS: 23% of patients with clinically mild disease had perforator diameter of 3mm or more, whereas, 62% of moderate and severe disease patients had incompetent perforator. Average diameter of perforator in CVI class 1 & 2 patients was 1.44mm whereas, in class 3 & 4 patients, it was 3.31mm and 3.58mm in class 5 & 6 patients. CONCLUSION: Diameter of perforator compare favourably with clinical severity of chronic venous insufficiency. This study may help to evolve patient management guidelines in perforator incompetence treatment.