According to the latest statistics, oral squamous cell carcinoma is the 9 th most common cancer to diagnose worldwide, especially in males and in the developing countries and cause for high mortality and morbidity. Oral potentially malignant disorders (OPMD's) are an important entity associated as precusors for most of these cases which are reversible. Hence, early detection of OPMD's can be very useful. Exfoliative cytology is a practically very easy and patient-friendly method to collect cells from these lesions. They can be subjected to a variety of analysis to help us detect oral cancer in advance. This review describes all the techniques have been used in early detection right from the conventional techniques to molecular diagnostics.