Abstract While the importance of vaccination services increases day by day, WHO declared vaccine hesitancy as one of the 10 threats to global health in 2019 due to the decrease in vaccination numbers in recent years. Raising parents awareness about childhood vaccines with adequate and accurate information is likely to positively affect vaccination decisions.Although the level of knowledge on this subject depends on parents being able to obtain information using the right sources, this situation can also be associated with a sufficient level of health literacy.This study aimed to evaluate how parents health literacy level affects their attitudes towards vaccines. This cross-sectional study was conducted through a facetoface survey with 400 parents of children under the age of 18 who applied to the Istanbul Faculty of Medicine, ChildHealthDiseasesPolyclinic. Asdata collection tools, a survey form including general approaches to preventive health services and knowledge level about vaccines, as well as the TSOY-32 and PACV were used. As a result of our study, the average of the correct answers given by the participants to the questions regarding their vaccination knowledge levels was determined as 12.1±4.3. The average health literacy general index score was found to be 33.6±4.5. It was determined that 2.5% of the parents had insufficient health literacy levels, and 67.8% had problematic or limited health literacy levels. Parents received a total score of 30.2±23.7 (13 (1-83)) from the PACV scale. It was determined that 13.5% of parents were hesitant about childhood vaccines. It was determined that individuals with vaccine hesitancy had lower general health literacy and vaccine knowledge levels, and they used the media and neighbors as sources of information at a higher rate. Additionally, it was determined that low level of knowledge about the vaccine(OR 1.4 95%CI 1.3-1.6). and using the media(OR 2.3 95%CI 1.0- 4.9) as a source of information poses a risk for vaccine hesitancy. Key messages • Providing community-based training to increase the health literacy level of parents will also create positive changes in vaccine hesitancy. • Community-based studies should be carried out regarding misconceptions about vaccines, especially those acquired from the media, and individuals should be made aware.