Endometriosis is described as the presence of functioning endometrial tissue outside the uterine cavity. Scar endometriosis is a rare disease, and is difficult to diagnose. The symptoms are nonspecific, typically involving abdominal wall pain at the incision site at the time of menstruation. It commonly follows obstetrical and gynecological surgeries. The diagnosis is frequently made only after excision of the diseased tissue. A case report of a patient with a troublesome scar after a caesarian section is presented. Surgical excision led to the diagnosis of scar endometriosis. The pathogenesis, diagnosis and treatment of this somewhat rare condition are discussed.