The aim of the present work was to assess the knowledge and attitudes of Brazilian General Dental Practitioners with regard to aspects of the aetiology, early diagnosis and prevention of oral cancer relevant for general dental practice. A convenience sample of 129 dentists in Brazil was randomly selected and asked to complete a questionnaire. Results of bi-variated analysis revealed that a self-perceived good knowledge regarding relevant aspects of oral cancer was statistically significantly associated with male gender (Chi square=4.59, P<0.05). Simple logistic regression revealed that male professionals were 2.9 times more knowledgeable than their female colleagues (OR=2.9, 1.1-8.1 95% CI, P=0.037), although, this association was not statistically significant when adjusted for age using multiple regression analysis (OR=2.7, 0.9-7.5 95% CI, P=0.059). There were no significant differences in relevant knowledge and attitudes of private compared with public dentists. Importantly, General Dental Practitioners who spent more than half of time of a patient's initial consultation undertaking a clinical examination were the more likely to detect oral cancer (Chi square=4.245, P=0.039) than those who set aside little time examining their patients. It is concluded that the knowledge of dentists in Brazil regarding relevant aspects of oral cancer is suboptimal, and may not be associated with any examined social-demographic variables. Further research is required to clarify the role of continuing professional education in improving the knowledge and attitudes of dentists relevant to oral cancer in Brazil.