The aim of the study is to study the impact of oral hygiene on the preservation of oral health in the city of Osijek. A total of 454 respondents participated in the research. As a research instrument, an anonymous questionnaire was created online (Google forms/surveys) and posted on an online platform. Respondents to the questionnaire were adults who agreed to voluntarily complete the anonymous questionnaire. The results of the research showed that the respondents believe that oral hygiene affects the preservation of oral health, which was confirmed by 99.3 % of the respondents. The results showed that people with a university degree who are employed have a better knowledge of the impact of oral hygiene compared to the less educated and unemployed population. People who stated a regular checkup as the most common reason for visiting a dentist also have better knowledge in comparison with those who chose a cavity filling as their most common reason. Respondents who brush their teeth more regularly are less afraid of dentists, have less carious teeth, do not wear dental braces, and have a better awareness of the impact of oral hygiene on maintaining oral health. The citizens of Osijek are aware of the impact of oral hygiene on maintaining oral health, but they do not carry out oral hygiene regularly.