The aim of this study was to evaluate the clinical and pathologic findings of patients with oral squamous cell carcinoma (OSCC) and compare them with the tumor-associated tissue eosinophilia (TATE) and serum eosinophilia (SE) quantifications. Clinical and anatomopathologic data were obtained from the medical records between 2006 and 2016. Tumors were classified according to histologic grade into 2 groups: well-differentiated carcinomas (group 1) and moderately/poorly differentiated (group 2). For analysis of TATE, the histologic slides were stained with Congo red, and stromal eosinophils were counted in 5 consecutive high-power fields using Image J 1.45 s. The SE count was performed by XE-2100 D Sysmex automated system after venous puncture. Of the 113 patients, 83 were from group 1 and 30 were from group 2. Most of the patients were white, smokers, alcoholics, and manual workers. Stage II of the disease predominated in both groups, and 8 patients died. There was no statistical difference between the groups in relation to TATE or SE (P = .16 and P = .19, respectively). However, there was a positive correlation between the TATE and SE (r = + 0.417, P = .048). TATE is directly associated with SE in OSCC patients, having no association with tumor aggressiveness, survival, or other clinical parameters. The aim of this study was to evaluate the clinical and pathologic findings of patients with oral squamous cell carcinoma (OSCC) and compare them with the tumor-associated tissue eosinophilia (TATE) and serum eosinophilia (SE) quantifications. Clinical and anatomopathologic data were obtained from the medical records between 2006 and 2016. Tumors were classified according to histologic grade into 2 groups: well-differentiated carcinomas (group 1) and moderately/poorly differentiated (group 2). For analysis of TATE, the histologic slides were stained with Congo red, and stromal eosinophils were counted in 5 consecutive high-power fields using Image J 1.45 s. The SE count was performed by XE-2100 D Sysmex automated system after venous puncture. Of the 113 patients, 83 were from group 1 and 30 were from group 2. Most of the patients were white, smokers, alcoholics, and manual workers. Stage II of the disease predominated in both groups, and 8 patients died. There was no statistical difference between the groups in relation to TATE or SE (P = .16 and P = .19, respectively). However, there was a positive correlation between the TATE and SE (r = + 0.417, P = .048). TATE is directly associated with SE in OSCC patients, having no association with tumor aggressiveness, survival, or other clinical parameters.