Objective: The aim of this research was to assess knowledge and attitudes of dental students of the Faculty of Medicine of the University of Rijeka, School of Medicine in Split and the School of Dental Medicine of the University of Zagreb about precancerous lesions of oral mucosa and to determine whether there are differences in knowledge and attitudes between students from fourth to sixth year of dental study of each faculty as well as between dental studies of different faculties. Materials and methods: In this paper, a cross-sectional study has been carried out using a questionnaire method. The questionnaire was composed of 30 questions. In the first part, general information about the study participant were gathered and, in the second part, knowledge and attitudes about precancerous lesions of oral mucosa. Students of fourth, fifth and sixth year of integrated dental study of the School of Medicine in Split, Faculty of Medicine of the University of Rijeka and the School of Dental Medicine of the University of Zagreb voluntarily participated in this research. A total of 128 students participated, 47 from the School of Medicine in Split, 33 from the Faculty of Medicine of the University of Rijeka and 48 from the School of Dental Medicine of the University of Zagreb. The gathered data were entered in the Microsoft Office Excel 2007 software and after that processed in the software package STATISTICA 11.0. Results: Students from the three selected faculties showed good knowledge on precancerous lesions of oral mucosa with an exception of a few questions where the percentage of correct answers was very low in study participants on all three faculties. Only 18 (47,4%) fourth year students correctly emphasized erythroplakia as precancerous lesion of oral mucosa with highest malignant alteration potential, however, this percentage rises significantly on the fifth (63,2%) and sixth (86,5%) study year. A small number of study participants, 9 (27,3%) from the Faculty of Medicine of the University of Rijeka, 7 (14,9%) from the School of Medicine in Split and 10 (20,8%) from the School of Dental Medicine of the University of Zagreb accurately stated all the characteristics of leukoplakia (most often an old age disease, non-transparent white patches, prolonged and frequent local irritations play a significant role in emergence), even though the majority of students who participated in the study (60%) recognized leukoplakia as the most common precancerous lesion of oral mucosa and accurately recognized the most risky clinical forms for malignant alteration. The largest share of study participants (22, i.e., 46,8%) from the School of Medicine in Split listed only the bottom of the oral cavity as the most at risk part of oral cavity for malignant alteration of precancerous lesion, while only 19 (40,4%) students accurately recognized all the most at risk parts of cavity. Dental students are not quite familiar with the newest scientific knowledge on risk factors for malignant alteration of precancerous lesions of the oral mucosa. Only 10,9% of dental students who participated in the study lists all possible risk factors. A great share of study participants (99, i.e., 77,3%) correctly recognizes that it is necessary to direct the patient to further diagnostic processing after two weeks of persistence of suspected lesion that does not respond to treatment. Dental students most often rated their knowledge about precancerous lesions of oral mucosa as very good (55, i.e., 43%), and as many as 99 (77.3%) mentioned Oral medicine as the course where they had the opportunity to hear the most about this topic. The largest share of students from selected faculties, 49 (38,3%) professes that during clinical exercises they had the possibility to carry out less than five clinical examinations of patients with precancerous lesions which is a devastating information given the fact that the importance of clinical experience for detection of precancerous lesions, and with this also prevention of oral cancer, is well known. Most of them, as much as 120 (93,8%) of study participants rated the level at which the patient is informed about the risk factors for developing oral cavity cancer as bad or extremely bad. Conclusion: In this paper, we have shown that there is a difference in knowledge and attitudes of dental students of the three selected faculties about precancerous lesions of oral mucosa even though it is not that significant, as well as that the knowledge on precancerous lesions changes as the academic years progress from fourth to sixth year. Role of students as future dental practitioners is crucial in early diagnostics of precancerous lesions and prevention of oral cavity cancer, therefore, the education and awareness-raising on this topic during education is of key importance.