Adolescents are a primary smoking prevention target of the Thai government. Assisting Thai adolescents to refrain from smoking will have long‐term benefits for the adolescents and also for the society.  The current study is designed as a prospective cohort survey aimed at evaluating national level tobacco control policy on the smoking behavior of both adolescents and adults. The baseline round (Wave 1) collected data in January and February 2005.  Wave 2 data was collected in August and September, 2006.

Immediately after the Wave 1 data collection was completed, the Thai Government implemented several new policies designed to reduce the incidence of smoking. These policies included the introduction of new pictorial health warnings on cigarette packets a ban on the display of cigarettes at the point of sale. A comparison of Wave 1 and Wave 2 data provides an opportunity to examine the impact of these new policies.