Objective — the aim of the present study was to identify the risk factors responsible for reflux persistence and recurrent varicose veins in the patients presenting with great saphenous vein (GSV) incompetence after isolated phlebectomy. Material and methods. All the patients underwent the ASVAL procedure (isolated phlebectomy) under local anaesthesia sparing the incompetent trunk of the great saphenous vein in 75 lower extremities of 67 patients. The presence of reflux in GSV was detected by duplex ultrasound within 12 months after surgery. The varicose veins recurrence rate was also registered. Evaluation of the independent risk factors of reflux persistence in GSV as well as of the development of varicose veins recurrence was performed by logistic regression. Results. Reflux in GSV within 12 months after the removal of isolated varicose tributaries was documented in 34% of the cases. The duration of reflux turned out to be a reliable predictor of the negative outcome of the risk treatment. The risk of reflux persistence during 1 year was roughly 13 times higher in the patients who initially had reflux in GSV below the mid-thigh. The recurrence of varicose veins developed in 13.5% of the patients. An important risk factor of the recurrence was the presence of reflux in the great saphenous vein one year after the ASVAL procedure. In such cases, the chances of recurrence increased by 264 times. Location of the varicose vein in the left lower extremity increased the chances for this condition to re-occur by 73 times compared with the right lower limb varicosis. Conclusion. Isolated phlebectomy is an optimal method for the treatment of the patients presenting with reflux in the great saphenous vein not lower than the mid-thigh with the location of the disease on the right lower extremity.