Oral cancer still represents a challenge in global health systems, the high morbidity and mortality is explained by the delay in diagnosis; a high percentage of cases present in stage III or IV at the time of initial diagnosis, complicating the prognostic factor. For early detection there are complementary aids such as toluidine blue, chemiluminescence, diffuse white light and loss of tissue auto fluorescence. However, biopsy is a fast, simple and effective method that provides us with a histopathological diagnosis and guides us in medical management and treatment. This article investigates and analyzes the role of biopsy in the early diagnosis of oral cancer, presents two patients diagnosed by this method, and highlights the importance of the preparation of first contact physicians and dentist.