Endometriosis is the presence of endometrial glands and stroma outside the endometrial cavity and is the most common known cause of pelvic pain. The number of women being diagnosed with the disease is increasing, but this may be reflective of improved diagnostic techniques. The aetiology is unknown, although the theory of retrograde menstruation remains dominant. Although pain around menstruation is the most frequently experienced symptom, dyspareunia, dyschezia, cyclical dysuria and extreme fatigue are all common. The 'gold standard' diagnostic technique is laparoscopic visualization, and the Royal College of Obstetricians and Gynaecologists (2006) recommends that surgical removal of all endometriotic lesions is the ideal. The experience of endometriosis can negatively affect all aspects of a woman's life and relationships, and this is consistently reported in research studies. This article discusses the aetiology and clinical aspects of endometriosis as well as giving an overview of empirical literature surrounding the experience of the disease. It provides nurses with the knowledge to be alert to the possibility of endometriosis as a diagnosis in women with a certain set of symptoms, in whatever healthcare setting they work.