Oral cancer is a fatal disease, which accounts for the 5th highest incidence of malignancy of male and the 7th in general population in Taiwan. The relative high prevalence of oral cancer in Taiwan is mainly because a 2.5 million high-risk group of population with smoking as well as betel nut chewing exist. Unfortunately, the new cases being found in medical center often present with a TNM stage III or IV level leading to a low 5-year survival. Therefore, it is generally accepted that prevention and screening or oral cancer at early stages or premalignant levels for the high-risk group of population are equally important to treatment. In this review article, we describe the nature of oral cancer and highlight the importance as well as various conventional and novel methods of screening of this disease.