Endometriosis is defined as the presence of functional endometrial tissue outside the uterus, causing diverse progressive symptoms such as infertility, pelvic pain, and dysmenorrhea. Although endometriosis has been described since the 1800s, the mechanisms responsible for its pathogenesis and progression remain poorly understood. It is well established that endometriosis grows and regresses in an estrogen-dependent fashion and the disease can be effectively cured by definitive surgery. However, prolonged medical therapy may be needed in most of the cases since conservative surgery is usually performed especially in young women. This treatment modality is often associated with only partial relief and/or recurrence of the disease. In the present review, up-to-date findings on the treatment of endometriosis will be briefly summarized. The outcomes of surgery in patients with endometriosis will be reviewed in terms of pelvic pain relief as well as infertility treatment largely based on recent Cochrane reviews and clinical reports. The efficacy of newer drugs including aromatase inhibitor, anti-tumor necrosis factor-alpha, and dienogest will be also reviewed based on recent clinical studies.