Background: The present study aims at evaluation of the prognostic value of tumor size including diameter, length, thickness, width, area, and volume in the prediction of nodal metastasis, local recurrence, and survival of oral tongue carcinoma. The results will have important implications for the management of patients.Methods: Eighty-five glossectomy specimens of oral tongue carcinoma were serially sectioned in 3 mm thickness for the tumor size evaluation with computer image analyzer.Results: Among all the tumor size parameters being evaluated, tumor thickness was the only significant factor for the prediction of local recurrence, nodal metastasis, and survival. With the use of 3 mm and 9 mm division, tumor of up to 3 mm thickness has 10% nodal metastasis, 0% local recurrence, and 100% 5-year actuarial disease-free survival; tumor thickness of more than 3 mm and up to 9 mm has 50% nodal metastasis, 11% local recurrence, and 77% 5-year actuarial disease free survival; tumor of more than 9 mm has 65% nodal metastasis, 26% local recurrence, and 60% 5-year actuarial disease-free survival.Conclusions: Tumor thickness should be considered in the management of patients with oral tongue carcinoma.