Many types of cancers develop in the oral and maxillofacial region. Squamous cell carcinoma is the most common cancer and constitutes over 90 percent of these tumors. Malignant transformation is a genetic process, which later makes a phenotyping change at the cellular level. Some cancers such as oral squamous cell carcinomas (OSCCs) develop from pre-malignant lesions and conditions. Despite advances in the treatment of OSCC, the 5-year survival rate remains approximately 50% due to inability of early detection of OSCC and precursor lesions. Early detection of oral cancer, especially in the premalignant stage, can decrease mortality and morbidity significantly. This article reviews some clinical, histopathological features and etiopathogenesis of pre-cancerous lesions of the oral cavity and skin of face and lip vermilion. A relevant English literature search in Pubmed, Science Direct, and Google Scholar was performed from 1930 to 2015. Full text of 191 articles met the specific inclusion criteria for this review.