Abstract Background Human papillomavirus (HPV) is the most common sexually transmitted infection in the United States and is linked to cervical, anal, vaginal, vulvar, penile, and oropharyngeal cancers. In the U.S. territory of Guam, the incidence of cervical cancer is six times higher in Micronesians and over three times higher for CHamorus than the U.S. population. Though nasopharyngeal cancer has other contributing factors beyond HPV infection such as smoking and drinking, the CHamorus, who are the Indigenous people of Guam, have an incidence rate of nasopharyngeal cancer 20 times that of the U.S. population. In Guam, HPV vaccination rate is sub-optimally short of the National Healthy People 2020 goal to have at least 80% of females and males between the ages 13-15 years complete the HPV vaccine series. In 2016, 55.8% females and 33.2% males completed the HPV vaccination. Objective Our study sought to analyze a representative sample of Guam residents to examine their knowledge, attitudes, beliefs, practices regarding HPV, and barriers to HPV vaccination. Methods The cross-sectional survey of 776 respondents included 38% males and 62% females. The three major ethnic groups in the sample were CHamoru (48%), Filipino (26%), and Micronesians (11%). Sixty-eight percent of the respondents had at least one child. The aggregated scores were calculated for the following scale items: attitude (A), knowledge (K), subjective norms (SN), and perceived behavioral control (PBC) regarding HPV. Results Almost 45% of respondents admitted that they do not have enough knowledge to have their children vaccinated. However, 88% of those respondents stated that they would have their children vaccinated if the doctor told them. Women had significantly higher mean scores than men for A, K, and PBC/SN. Participants with more than high school education and higher incomes have significantly higher mean scores for all three measures. There were significant differences among different ethnic groups, with Micronesians having the lowest average score for all three measures. There were no significant differences between participants who had their children vaccinated and those who did not. Only 48% of respondents with children reported having their children vaccinated. Only ethnicity and having insurance were significant predictors of HPV vaccination. The respondents with medical insurance were almost three times as likely to have their children vaccinated for HPV (OR=2.8; 95% CI: 1.4, 5.2) Conclusions The results highlighted the significance of the physician’s role in having the HPV vaccination. Our results will serve as a guide to implement effective strategies for the development of targeted behavioral interventions and to develop appropriate interventions to increase the HPV vaccination uptake on Guam. Citation Format: Ana Joy Mendez, Lilnabeth Somera, Grazyna Badowski, Angelina Mummert, Lucy Castro, Angrenilda Antolin. Knowledge, attitudes, beliefs, practices regarding human papillomavirus (HPV), and barriers to vaccination against HPV infection: A cross-sectional survey of Guam residents [abstract]. In: Proceedings of the AACR Virtual Conference: Thirteenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2020 Oct 2-4. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(12 Suppl):Abstract nr PO-070.