This is a competitive renewal application for a Fogarty International Center Tobacco control research and capacity building project focused in Argentina. This project is based in the Southern Cone of South America that has the highest attributable mortality to tobacco in the Americas. In the first funded cycle, we developed methods to recruit and survey a cohort of 3,500 13 to 15 year old adolescents from Jujuy, a province in the Northwest of Argentina with a predominantly indigenous population. We have completed a baseline and two follow-up surveys and will be able to generate smoking initiation and transition rates that will include 3 years of follow up with a final survey in 2007. In this proposal we aim to 1) Use the cohort data to develop an intervention to prevent tobacco use among diverse youth in Northwest Argentina;2) Implement and evaluate a system-based smoking cessation intervention using a randomized trial design among physicians to promote smoking abstinence and quit attempts in their patients who smoke over a one-year period;3) Continue to follow the cohort for three additional years or until age 20;4) Develop policy interventions to promote smoke free indoor space and regulation of tobacco products advertising by continuing to analyze the tobacco industry documents on Argentina, using data generated from the heart disease policy model, and evaluation of tobacco use in popular films in Argentina;and 5) Build research capacity by expanding training opportunities in Argentina at all levels, selecting 2 scholars annually to visit UCSF for development of tobacco control research methods, and support the application of promising scientists in Latin America to the Tobacco Control Research Fellowship at UCSF.