Around the world, healthcare services face increasing demands from aging populations, with high disease burdens and expensive new ways of managing them. Many new drugs and other health technologies cost considerably more than those they supplant, but may only give a proportionately small health gain. As a result individuals, insurance companies, health maintenance organizations and national health services are forced to take decisions on which new therapies can be afforded for whom. The experience of the UK National Institute of Clinical Excellence (NICE) illustrates some of the means and pitfalls of making such decisions.