Introduction: In oral cavity, the tongue is the most common site prone to development of squamous cell carcinoma (SCC). Considering malignant transformation as a cellular stress, the expression of heat shock proteins (HSPs) may be affected in this process. In this study we assessed the expression of HSP105 and HSP27 as two of the most interested stress proteins and investigated their relationship with grade and stage of the tongue SCC. Material and Methods: Fifty-six specimens including 31 early and 25 advanced tongue SCC were gathered. All specimens were graded histologically from I to III. Sixteen sections of normal oral mucosa were used as control group. The cellularity and intensity of HSP105 and HSP27 expression were studied immunohistochemically in both case and control groups. Results were expressed by histochemical score (HSCORE). Results: Significant differences were observed between expression of HSPs and stage of the disease. From early to advanced stage, the expression of HSP105 and HSP27 increased and decreased, respectively. There was no relationship between histological grade of lesion and HSCORE of HSP105 expression (P=0.5), although, HSP27 expression had reverse relationship with the SCC histological grade. Conclusion: HSP27 and HSP105 may be indicated for prognostic purposes in evaluation of tongue SCC. HSP 27 may be used for more accurate microscopic grading of tongue SCC. Increased expression of HSP105 in advanced stage may lead to using this protein for immunotherapy of tongue SCC. © Medicina Oral S. L.