Objective: To report a case of iatrogenic leg ulcer after subfascial endoscopic perforator surgery (SEPS). Design: Case report. Setting: Department of Vascular Surgery, Milton Keynes Hospital, a district general hospital. Patient, intervention and results: A 57-year-old woman underwent SEPS for a venous ulcer secondary to an incompetent perforating vein. Post-operatively she developed a new ulcer directly over the site of the divided perforator. The ulcer healed completely with conservative bandaging treatment after 4 months. Conclusion: We describe a complication of SEPS not previously reported. The perforating artery might have been divided inadvertently instead of the perforating vein. It is important to positively identify the perforating vein during SEPS before its division, especially in the presence of mixed arteriovenous disease.