Worldwide, oral cancer has one of the lowest survival rates. It is well recognized that survival rates are improved if the disease is treated in its early stages. The aim of this study was to assess the effectiveness of screening methods in decreasing the mortality of oral cancer. A systematic review on the effectiveness of oral cancer screening was performed using all publications in MEDLINE, CANCERLIT, EMBASE, and Cochrane CCTR between 1966 and September 2002. The evidence was evaluated using the standardized methodology of the Cochrane Collaboration. The search strategy revealed 1,389 citations. From these, 100 potentially relevant articles were selected for review. However, only one randomized controlled study using visual examination as the method for screening fulfilled the selection criteria. Given the limitation of evidence and the potential methodological weakness in the included study, it is valid to say that there is no evidence to recommend inclusion or exclusion of screening programs for oral cancer using visual examination in the general population. In addition, no robust evidence exists that indicates whether other screening methods including toluidine blue, fluorescence imaging, or brush biopsy are either beneficial or harmful. Further high-quality studies to assess the efficacy and effectiveness of screening are required. Additional investigations aimed at elucidating the natural history of oral cancer and evaluating the effectiveness of prevention and opportunistic screening in high-risk groups are needed. A greater understanding of the genetic basis of oral cancer is an essential prerequisite to the development of molecular markers for screening.