Global climate change, increasing human population and improved economic status in populous developing countries are causing an expansion of poultry production under hot ambient temperatures. High environmental temperatures have a negative impact on productivity and health in poultry. There is evidence for a substantial genetic component to the bird’s response to high temperature, including single genes of major effect as well as complex multigenic control. Therefore, it is feasible and desirable to identify such genes and genomic regions, and to breed chickens that can adapt to high temperatures. Contemporary genomic approaches will yield insight into the genetic mechanisms that contribute to a bird’s ability to cope with a hot environment.