In 2005, the European Union (EU) commissioned a study as part of an EU-wide antismoking campaign. The study was conducted by a consortium of EU companies. Our research reanalyzes the EU data, based on interviews with over 25,000 consumers in 25 countries. This paper focuses on Eastern EU countries and addresses the potential effects of source misattribution. We built a conceptual model linking comprehension of and attitude toward the campaign with outcome measures: responsible thinking toward smoking and intention to quit. Our analysis suggests that source attribution plays a moderating role in the relationship between message comprehension and the two outcome variables.