AIM OF THE RESEARCH: The aim of the research is to examine the knowledge and attitudes of patients regarding oral cancer. STUDY DRAFT: Cross-sectional observational study. RESPONDENTS AND METHODS: The research was conducted in June 2022 through an anonymous questionnaire, and the respondents were adult patients treated in dental offices in the Republic of Croatia. One hundred and one respondents participated in the research. RESULTS: The respondents were predominantly women (51.5 %). The average age was 48.3. The majority (58.4 %) had completed secondary education. Among the respondents, 36.6 % are smokers, while 41.6 % consume alcohol. The vast majority of the respondents (95.1 %) were right to believe that oral cancer most commonly occurs in men and people over 40 years of age. Eight percent of the respondents marked all of the risk factors, and significantly more younger people recognized a larger number of risk factors. Fourteen percent of the respondents marked all of the symptoms suggestive of cancer, 2 % of the respondents marked all of the diagnostic techniques, and 18 % marked all of the treatment methods. The tongue, as the most common cancer localization, was correctly marked by 41 % of the respondents. The vast majority of the respondents (92.1 %) were right to believe that oral cavity cancer is not contagious. Thirty-nine percent of the respondents believe that doctors of dental medicine have informed them on oral cancer, and 18.8 % of the respondents claim that they were tested for cancer. The majority of the respondents (67.3 %) want to learn more about oral cancer, 66.3 % want to be advised more frequently on its prevention, while 62.4 % want to be examined more frequently. CONCLUSION: The knowledge of respondents in the Republic of Croatia regarding oral cancer is insufficient. The respondents show a positive attitude and a motivation for education, counseling, and preventive examinations. Therefore, it is necessary to introduce systematic patient education regarding oral cancer.