Background: Social and environmental changes have accompanied the ongoing rapid urbanisation in a number of countries during recent decades. Understanding of its role in the health-risk transition is important for health policy development at national and local level. Thailand is one country facing many of the health challenges of urbanisation. Objective: To identify potential associations between individual migration between rural and urban areas and exposure to specific social, economic, environmental and behavioural health determinants. Design: Baseline data from a cohort of 87,134 Thai open university students surveyed in 2005 (mean age 31 years). Four urbanisation status groups were defined according to self-reported location of residence (rural: R or urban: U) in 2005 and when the respondent was 10-12 years old (yo). Results: Fourty-four percent were living in rural areas in 2005 and when they were 10-12yo (Group RR: ruralites); 20% always lived in urban areas (UU: urbanites); 32% moved from rural to urban areas (RU: urbanisers); 4% moved in the other direction (UR: de-urbanisers). The ruralites and urbanites often were the two extremes, with the urbanisers maintaining some of the determinants patterns from ruralites and the deurbanisers maintaining patterns from urbanites. There was a strong relationship between urbanisation status, from RR to RU to UR to UU, and personal income, availability of modern home appliances, car ownership, consumption of ‘junk food’ and physical inactivity. Urbanisers reported worse socio-environmental conditions and worse working conditions than the other groups. De-urbanisers had the highest rates of smoking and drinking. Conclusions: An urbanisation measure derived from self-reported location of residence gave new insights into the health risk exposures of migrants relative to permanent rural and permanent urban dwellers. Living in urban areas is an important upstream determinant of health in Thailand and urbanisation is a key element of the Thai health-risk transition.