Objective: To elucidate the chemosensitivity of human tongue squamous cell carcinoma Tca83 cell line to all-trans retinoid acid (RA) and to determine the potential genetic factors mediating this sensitivity. Methods: RA in the amounts of 0.1, 1, and 10 µMol/L were used to treat human cell line Tca83 in vitro. Cell apoptosis as well as Fas/FasL expression were analyzed by TUNEL, RT-PCR, and immunohistochemistry approaches. Results: RA in the amounts of 1 and 10 µMol/L RA began to inhibit cell proliferation at day 3 and had induced cell apoptosis on day 5. Both Fas and FasL could be detected in the treated and untreated cells. RA upregulated Fas mRNA and protein expression at day 5. RA had no obvious effect on FasL expression. Conclusion: The results suggest that apoptosis induced by RA may result from the enhancement of Fas gene transcription and translation.