OBJECTIVES: To examine the differences in knowledge, attitude, and vaccination decision among Thai women who had exposed and not exposed to the public information concerning HPV vaccine. METHODS: : Structured interviews were carried out in Bangkok from June to September 2008 among female students in 4 high schools and 2 universities, and female office workers, in public and private companies, including mothers, who had at least one daughter. The total number of respondent was 1568. The interviews included socioeconomic status, sexual activity, whether or not they had exposed to the public information about HPV vaccine, level of knowledge about cervical cancer and HPV vaccine, attitude toward the vaccine, and vaccination decision. Descriptive statistics and regression were used in the data analysis. RESULTS: : The interviewees who had exposed to HPV vaccine-related information had significantly better knowledge about the causes of cervical cancer than those who not exposed to the information. However, there was no significant difference in the level of knowledge about the vaccine between the two groups. The study also found that those who had exposed to HPV vaccine-related information and misunderstood that the vaccine could prevent other sexual transmitted infections; the vaccine could treat early cancer; or the vaccine was equally effective in those with and without sexual activities, were more likely to accept the vaccine than the others. CONCLUSIONS: The public information about the HPV vaccine would lead to undesirable effects to public health such as irrational vaccination. It is important that respective authorities take serious actions to regulate public advertisement of health product as well as empower consumers to protect themselves from inaccurate information.