The role of exfoliative cytology in the screening for oral cancer has never achieved the same success as it has for diagnosing cancer of the uterine cervix. Yet the recent application of quantitative and immunocytochemical techniques has,to some extent, refined its potential role, However, the absence of a marker, present in all malignant lesions but never seen in benign lesions. Limits its clinical utility and argues for the identification of a combination of markers, whose sensitivity and specificity require evaluation. It may well be that oral exfoliative cytology will enjoy its greatest success, not so much in screening, but rather as providing samples of DNA from biopsy proven oral cancers. Greater understanding of the type of mutation present may, in the future, predict not only tumour behaviour, but also its response to both traditional and novel forms of therapy.