This study investigated if tumor-associated tissue eosinophilia (TATE) could be associated with the process of tissue invasion in oral squamous cell carcinomas (OSCCs) and its influence on patient's prognosis. Forty-three patients treated for OSCCs with or without lymph nodes involvement, at A. C. Camargo Cancer Hospital, Brazil, were selected for TATE analysis. Two degrees of tissue eosinophilia were established in OSCC: absent/mild and intense. The TATE was evaluated in relation to the clinicopathological features and prognostic value using χ2 test and the Kaplan–Meier method. Most of the patients with OSCC in advanced clinical stage presented muscular infiltration and significantly intense TATE whereas those with tumors in early stage frequently showed absent/mild eosino-philia (P = .009). The TATE showed no prognostic value for 5-year and 10-year survival rates of the OSCC. These findings suggest that intense TATE seems to reflect the stromal invasion of the OSCCs that occur in advanced clinical stage.