IntroductionGreat saphenous vein (GSV) harvest is common practice in vascular and cardiothoracic surgery. Thrombosis of the proximal remnant of vein with propagation into the femoral vein has not been reported before.Case reportThe distal half of the GSV was harvested for remote grafting of an axillary artery injury. Three months later the patient presented with thrombosis of the proximal remnant with extension of the thrombus into the femoral vein. This was successfully treated by high ligation and extraction of thrombus.DiscussionLeaving a proximal remnant of the GSV in the thigh can lead to thrombosis, and the potential lethal complication of thrombus extension through the sapheno-femoral junction with the possibility of pulmonary embolism. We suggest that if the great saphenous vein is harvested in the distal thigh, the sapheno-femoral junction should be flush-ligated to prevent this complication.