PURPOSE: Anatomy and morphology of superficial veins vary from patient to patient. Thorough assessment of variations is mandatory for successful treatment of primary varicose vein. Alos in complex case clinical examination alone is unable to achieve diagnostic goals. Duplex scan is a highly accurate, noninvasive technique that can provide both anatomic and physiologic information. METHODS: Thirty-eight legs in 30 patients with primary varicose veins were examined clinically first then with portable doppler. Patients then underwent duplex scanning by surgical team and results of tests were compared with other clinical examinations. RESULTS: On duplex scanning, 25 legs (66%) had saphenofemoral junction (SFJ) incompetence, 9 legs (24%) had saphenopopliteal junction (SPJ) incompetence and 4 legs (10%) had perforator incompetence. The respective sensitivity of clinical examination with portable doppler in SFJ, SPJ was 91.6%, 81.8%. CONCLUSION: Clinical and doppler assessment was unreliable. Routine preoperative duplex scanning is likely to reduce recurrence by identifying sites of reflux with greater accuracy.