In its October 2008 issue, Nature Reviews Genetics presents a Supplement on Genomic Medicine in Developing Countries. At the point when the theory is about to be translated into practice in genomic medicine, this collection of five Perspective articles describes human genome variation studies taking place in Mexico, India, Thailand, and South Africa. The articles in the Supplement discuss the challenges and opportunities facing these and other countries in the developing world as they begin to harness genomics for the benefit of their populations, and highlights areas in which the international human genomics community needs to take a more forward-thinking approach. The Supplement is free to access online.