Background: The study is based in post-apartheid South Africa and looks at the health and well being of households in the rural northeast. Temporary migration remains important in South Africa because it functions as a mainstay for income and even survival of rural communities. The economic base of rural South Africans is surprisingly low because there is high inequity at a national level, within and between racial groups. There has now been a democratic system in place for 15 years and there is no longer restriction of mobility, but there remain high levels of poverty in rural areas and rising mortality rates. Migration patterns did not change after apartheid in the manner expected. We need to examine consequences of migration and learn how to offset negative impacts with targeted policies. Aims: To determine a relevant typology of migration in a typical rural sending community, namely the Agincourt sub-district of Mpumalanga, South Africa, and relate it to the urban transition at a national level – Paper (I) . To evaluate the dynamics of socio-economic status in this rural community and examine the relationship with migration – Paper (II). To explore, using longitudinal methods, the impact of migration on key dimensions of health, including adult and child mortality, and sexual partnerships, over a period of an emerging HIV/AIDS epidemic – Papers (III), (IV) and (V). Methods: The health and socio-demographic surveillance system (HDSS) is a large open cohort where the migration dynamics are monitored as they unfold. They are recorded as temporary or permanent migration. Settled refugees are captured using nationality on entry into the HDSS. Longitudinal methods, namely a household panel and two discrete time event history analyses, are used to examine consequences of migration. Results: Migration features prominently and different types have different age and sex profiles. Temporary migration impacts the most on socio-economic status (SES) and health, but permanent migration and the settlement of former refugees are also important. Remittances from migrants make a significant difference to SES. For the poorest households the key factors improving SES are government grants and female temporary migration, while for less poor it is male temporary migration and local employment. Migration has been associated with HIV. Migrants that return more frequently may be less exposed to outside partners and therefore less implicated in the HIV epidemic. There are links between migration and mortality including a higher risk of dying for returnee migrants compared to permanent residents. A mother’s migration can impact on child survival after accounting for other factors. There remains a higher mortality risk for children of Mozambican former refugee parents. Interpretation: Migration changes the risks and resources for health with positive and negative implications. Measures such as improved transportation and roads should be seen as a positive, not a negative intervention, even though it will create more migration. Health services need to adapt to a reality of high levels of circular migration ranging from budget allocation to referral systems. Data should be enhanced at a national level by accounting for temporary migration in national censuses and surveys. At individual level we can offset negative consequences by treating migrants as persons striving against adversity, instead of unwelcome visitors in our better-off communities.