To successfully establish a metastasis from an invasive carcinoma, the first step involves the degradation of the underlying basement membrane, which is mainly made up of type IV collagen. Matrix metalloproteinases (MMPs)-2 and -9 are thought to play an important role in its degradation because of their ability to destroy this type of collagen. In order to evaluate the prognostic significance of these proteases, we studied the expression of MMP-2 and -9 in series of 68 OSCC by immunohistochemistry. Of the oral carcinomas, 28% (n = 19) expressed MMP-2, and 17.6% (n = 12) expressed MMP-9. MMP-2 immunoreactivity was significantly higher in patients with alcohol consumption (p = 0.028) (OR = 4), and in those younger than 60 years (p = 0.041). MMP-9 immunostaining showed statistically significant association with the tumor grade of differentiation (p = 0.019), the T-stage (p = 0.05), and also with the alcohol intake (p = 0.04) (OR = 7.67). In the present study, although not statistically significant, we observed that immunoexpression of MMP-2 and MMP-9 was stronger in patients with lymph node metastasis (OR = 1.65 and 2.29, respectively). In patients without regional lymph node metastasis, positive MMP-9 immunostaining was related to poor survival rates (p = 0.02; OR = 5.8). MMP-2 and -9 are involved in the invasion process of oral cancer, and MMP-9 is related to poor prognosis in the subset of patients without neck node metastasis. Ethanol could enhance the carcinogenetic process in oral cavity through its influence in the expression of MMP-2 and -9.