With 2.1 billion inhabitants, the region of East and Southeast Asia is home to one-third of the global population, notably thanks to China, the world's most populated country, which alone has 1.3 billion citizens. This chronicle provides an overview of the major sociodemographic and health trends in the region since the 1950s, along with a statistical assessment of the most reliable recent data on each country. It includes information on population size and structure, fertility and its intermediate variables, nuptiality, mortality and health, international migration, urbanization and access to education. The region is marked by the extremely rapid progress achieved in reducing mortality and controlling fertility over recent years. Life expectancy at birth has risen from 40 to 70 years since the early 1950s and, thanks to vigorous and sometimes interventionist family planning programmes in certain countries, fertility in the region as a whole is now below replacement level. These changes are raising new demographic challenges, the most immediate of which are population ageing, changing migration patterns and, in some countries, a sex-ratio imbalance resulting from massive use of sex-selective abortion.