Improvement of survival rate and quality of life after treatment of oral squamous cell carcinoma as well as cost reduction requires reliable early diagnosis of the tumor and its precursor lesions. Four different screening methods are primarily employed: toluidine blue staining (visually detected lesions: sensitivity 70-100%, specificity 25-67%), photodynamic diagnosis (sensitivity 94-99%, specificity 60-89%), autofluorescence (no data published so far) and modern oral cytology (sensitivity 80%,specificity 95-100%). Additional analytic procedures such automated image analysis, DNA image cytometry and immunocytochemistry can be used to enhance the low sensitivity of conventional oral cytology. While these methods have achieved sensitivity and specificity approaching 100%, the studies involved clearly-defined entities such as large oral squamous cell carcinomas and aphthae. The modern and methodenhanced oral cytology is a simple, value-based and inexpensive tool for early diagnosis of oral squamous cell carcinoma and its precursor lesions. Surgical biopsy and histopathological examination remains the gold standard for definitive diagnosis.