Endometriosis is a relatively common gynaecological problem in women of reproductive age. Extra pelvic endometriosis has been described in many unusual sites but most frequent location is in abdominal wall. It is usually associated with operations in which uterus is opened. Due to increased incidence of caesarean section, incidence of scar endometriosis is increasing. The cause of endometriosis remains controversial. The most accepted theory is the iatrogenic transplantation of viable endometrial tissue to wound edge. Suspicion of diagnosis is by characteristic cyclic pain and swelling of scar. Hormone has no role in its treatment. Surgical excision is the choice of treatment.