Since 1985, social marketing has been a major component of the Canadian government's efforts to reduce tobacco use. Social advertising has been the linchpin of Health Canada's antitobacco social marketing program. Together with legislative measures and antitobacco programming that targets vulnerable segments of the population, social marketing is part of a centrally coordinated and multipronged strategy to reduce tobacco demand in Canada. This chapter describes how research is used in the design, implementation, and evaluation of antitobacco advertising. It describes ad-concept focus testing, awareness monitoring, and impact assessment, as well as two segmentation frameworks that have helped to define the target audience for new messages and evaluate the impact of advertising in changing the attitudes and behaviors of the population.