The decline of fertility with age and its possible causes are discussed; in particular the effect of ageing of oocytes and the uterus, and the effect of the ageing processes on the results of in-vitro fertilization (IVF) and embryo transfer in women aged > or =40 years. The role of prestimulation testing in older women is considered together with the importance of screening and counselling these patients about the likelihood of achieving a live birth. The potential problems that they may face should they become pregnant are reviewed, together with the role of oocyte donation as an alternative treatment for patients with reduced ovarian reserve. Possible ways of improving the chances of achieving a live birth in older women using their own oocytes are reviewed, including the use of more effective stimulation protocols, assisted embryo hatching and co-culture and high order embryo transfer. The outcome of pregnancies in older women and some of the ethical problems relating to their treatment are also discussed.