Objectives: To examine the frequency of pathological lesions of the oral mucosa, suspected potentially malignant oral lesions and lesions suspicious for oral cancer in persons who responded to the examination for early detection of oral cancer during the promoting of the Oral, Head and Neck Cancer Awareness Week in April 2022 and 2023. in the clinic for oral medicine of the University Hospital of Split. Materials and methods: 440 subjects, who responded to a preventive examination for early detection of oral cancer as part of the organized Open Day, voluntarily participated in the research. The age range of the respondents is from 18 to 93 years. A detailed medical history was taken from all subjects. During the non-invasive clinical examination of the oral cavity, data on the condition of the oral mucosa and the type of lesion that was found were recorded. Patients who were found to have a pathological lesion of the oral cavity were referred for further specialist treatment. Subjects who were found to have a lesion suspicious of cancer were referred to the clinic for maxillofacial surgery in order to perform a biopsy and pathohistological analysis of the lesion. Results: 208 (47.3%) men and 232 (52.7%) women participated in the research. The mean age was 62.8, while the median was 66 years. A total of 32 (7.3%) precancerous lesions were found. Of these, 23 (5.2%) had clinical findings of erosive forms of oral lichen planus. Seven (1.6%) pathological changes were associated with oral cancer. When asked about daily alcohol consumption, 112 (25.5%) answered yes, while 104 (23.6%) declared themselves as smokers. Conclusion: A pathological change suspicious of cancer was found in seven subjects out of 440 examined. In this study, a total of 117 pathological changes of the mucous membrane were found, of which 32 were characterized as potentially malignant lesions. The most frequently found potentially malignant lesion was the erosive form of oral lichen planus. A total of 104 respondents required an additional specialist examination, which for the majority was an examination by an oral medicine specialist. Of the seven subjects in whom a lesion suspicious of cancer was found, four of them denied the consumption of alcohol and tobacco products.