Background: Recurrent scar endometriosis was thought to be caused by implantation theory; this is a rare case to have recurrent CS scar endometriosis for the third time in different sites of scar of one CS, which could oppose this theory; we are presenting 34 years of patient complaint of recurrent painful swelling related to menses, previously excised twice and proved to be endometriosis by histopathology. Surgical excision of this swelling was done and proved to be endometrioma for the third time. 
Conclusion: Implantation theory as a cause of scar endometriosis should be revised as it cannot support the recurrence of endometrioma for a third time.