Endometriosis is an enigmatic disease of menstruating females affecting the reproductive life. We report herein a case of perineal endometriosis in a 33-year-old woman. The patient presented two rounded, thickened plaques bilaterally on the perineum for about four year. The plaque on the right side was located mainly at the episiotomy scar. Histologic examination showed confirmative feature of glandular structures embedded in the cellular stroma and predecidual changes of late secretory phase of endometrium.