Demography is the study of the size and composition of populations. Populations change size through births, deaths and net-migration. Over time, mortality, fertility and migration patterns create populations that may be large or small, young or old, growing or declining. Rural and remote Australia has a unique demography that determines its health problems and health service needs. The tendency of young adults to leave rural and remote areas for cities means that they leave behind communities which are, on average, older than those found in the cities. Rural and remote women have slightly more children at significantly younger ages, but because of out-migration, the actual number of babies born outside of the cities is smaller than would be expected. Most rural and remote areas already have a high proportion of their population over 65 years old. Many communities with an older population are declining in absolute numbers but the need for health services may be greater than required for smaller, younger communities. In contrast to the trends in total population, the rural and remote Aboriginal and Torres Strait Islander population is growing rapidly. This is the result of a higher proportion of young people, higher fertility rates and lower rates of moving to cities. The health characteristics of rural and remote Australia increasingly reflects the higher morbidity of Indigenous and older people. Responding to this demographic destiny is the present and future challenge.