Policies on health warning labels for cigarette packaging are rapidly evolving, and present important communication opportunities to promote smoking cessation and prevent smoking uptake. Since Canada first implemented pictorial health warnings on tobacco packages in 2001, more than 30 countries have implemented pictorial warnings, and many more countries are developing regulations, including the US. This symposium will provide an overview of health warning label policies and recent research on their impact. The first presentation will provide an overview of labelling practices around the world, including trends in the adoption of pictorial versus text warnings; the size and position of warnings; inclusion of telephone “quitline” information; warnings on the “interior” of packages; and emission/toxic constituent labelling. The second presentation will show results from a study in the US and Mexico to assess effectiveness of 100 different types of messages and “executional styles” (e.g., fear-arousing gruesome images, symbolic images, non-graphic depictions of human suffering, and testimonial information). This presentation will also show results from an evaluation of the pictorial warnings that the Food and Drug Administration proposed for cigarette packaging in the US. The third presentation will show results from experimental studies and focus groups conducted in Mexico to determine the best textual complements to pictorial warnings, with a particular emphasis on the testimonial vs. factual content, and how some content may have different impacts in important population subgroups. The fourth presentation will examine synergies between the main and interactive effects of pictorial health warning labels and a linked media campaign in Mexico.