We examined P53 mutation and invasion front grading (IFG) in 30 cases of oral squamous cell carcinomas (OSCCs). The association of P53 mutation and IFG scores with clinicopathological parameters was evaluated. P53 mutation existed in exon 5-8 in 15 out of the 30 OSCCs (50%). The incidence of P53 mutation was not associated with age, gender, N value and TNM stage. However, there was a significant correlation between P53 mutation and T value (P=0.046). There were no statistically significant correlations among the clinicopathological parameters and IFG. Interestingly, The IFG score in OSCCs with P53 mutation was significantly higher than that in OSCCs without P53 mutation (P<0.001). These results suggest that the high incidence of P53 mutation is a major mechanism of OSCC carcinogenesis. The presence of P53 mutation indicates the most anaplastic fields in the invasive areas of the tumors, which may predict poor prognosis for the patients.