Endometriosis is best treated by surgical excision. This can be accomplished either by excision of the endometriosis with reproductive tract preservation or by excision of endometriosis with hysterectomy. This latter approach eliminates endometriosis in the muscle of the uterus (where it is called adenomyosis) and is especially effective for pelvic pain. Ovarian preservation can be considered using hysterectomy if the surgeon excises most of the endometriosis. Techniques to excise endometriosis, including rectosigmoid disease, and perform hysterectomy are detailed in this chapter.