The aim of this study was to investigate the relationship of matriptase-2 expression with the clinicopathologic characteristics, the histologic grade, and patient survival in oral squamous-cell carcinoma (OSCC). Immunohistochemical analysis of matriptase-2 expression was performed in 102 surgical specimens from patients with OSCC. The immunohistochemical results were further verified by quantitative real-time reverse transcription-polymerase chain reaction. The immunostaining intensity was scored on a scale ranging from 0 (absence of staining) to 3 (intense staining). The distribution score was determined by the percentage of stained cells on a scale ranging from 0 (<5%), 1 (5% to 25%), 2 (25% to 50%), 3 (50% to 75%), to 4 (75% to 100%). The immunoscore of matriptase-2 expression was the product of the above 2 scores and ranged from 0 to 12 for analysis. Faint matriptase-2 immunostaining was observed in the non-neoplastic oral mucosal epithelia. The matriptase-2 immunoscore was significantly higher in well-differentiated OSCCs than in poorly differentiated tumors (P=0.001). Moreover, a reduced matriptase-2 immunoscore was inversely correlated with the tumor size (P=0.017), a positive nodal stage (P=0.008), distant metastasis (P=0.032), and a late clinical stage (P=0.001). A lower immunoscore of matriptase-2 expression revealed a significant association with poor survival (P=0.003). Our results demonstrate that the inverse expression of matriptase-2 correlates with tumor progression and an advanced TNM stage, and has a poor prognosis in patients with OSCC. These findings suggest that the expression of matriptase-2 may be both a prognostic marker and a potential therapeutic target for this cancer.