bcl-2 oncogene prolongs cell survival by inhibition of apoptosis. p53 tumor suppressor gene participates not only in cell proliferation control but also in induction of apoptosis. The expression of both bcl-2 and p53 proteins in 52 primary tongue squamous cell carcinomas (SCCs) was immunohistochemically explored in correlations with clinico-pathological features, patient's prognosis and apoptosis index (AI) of this tumor type. bcl-2 and p53 expression were identified in 26/52 (50%) cases and 31/52 (60%) cases, respectively. The frequency of bcl-2 expression was associated with tumor histologic grade (P = 0.0128) and marginally with mode of tumor invasion (P = 0.0671) but not with lymph nodal involvement. The frequency of p53 expression was associated with mode of tumor invasion (P = 0.0458) and pN status (P = 0.0224) but not with tumor histologic grade. Moreover, the three combined bcl-2/p53 staining patterns of bcl-2-/p53-, bcl-2+/p53- and bcl-2-/p53+, and bcl-2+/p53+ were significantly correlated with tumor histologic grade (P = 0.0299), mode of tumor invasion (P = 0.0022) and pN status (P = 0.0024). In addition, the frequent appearance of bcl-2 protein expression was associated with a decrease in AI (P = 0.0290). Our results suggest that the combined investigation on the two biological markers may have value in assessment of tumor aggressiveness, and that the suppressing mechanism of bcl-2 oncogene in regulation of apoptosis preserves in tongue SCC.