Endometriosis is a chronic oestrogen-dependent condition that affects 10% of women from puberty to menopause. It is characterised by the presence and proliferation of endometrial-like cells outside the uterine cavity, generally within the pelvis. Endometriosis can present as superficial or deep peritoneal lesions, ovarian endometrioma or deep rectovaginal disease. The two hallmark symptoms of endometriosis are pelvic pain and infertility resulting in poor quality of life. There is no correlation between the extent of the disease and severity of symptoms. The true prevalence of the condition is not known, as it requires a laparoscopy to confirm the diagnosis. It is found in up to 30% of women with infertility and in 45% of those with pelvic pain. While there are several theories of pathogenesis, an interplay of genetic, hormonal, environmental and immunological factors is implicated in the development of endometriosis in susceptible women. Symptoms are managed with a combination of hormonal treatment and laparoscopic ablation or excision of lesions for pain and usually assisted reproduction for infertility. Endometriosis is prone to recurrence after treatment, requiring multiple contacts with healthcare and repeat surgery. Management of endometriosis requires an individualised approach based on the woman’s age, predominant symptoms and priorities, which are subject to change over time.