We describe a case of chest wall ulcer in a breast cancer patient after radiation therapy being treated at the Department of breast surgery, K Hospital. Clinical case: A 64-year-old female patient, diagnosed with right breast cancer, underwent modified radical mastectomy, adjuvant chemotherapy and radiotherapy for the first time in 2001; 2nd radiation in 2004 due to right chest wall recurrence, in 2020 the patient developed chest wall ulcer and underwent chest wall reconstruction surgery using latissimus dorsi flap.