Objectives: To examine the utility of established prognostic variables in patients with oral carcinoma and a clinically negative neck. Study design: Retrospective cohort study. Methods: The distribution of occult metastases was assessed in 105 oral cancer patients with no clinical or radiological evidence of nodal disease. Predictors for nodal metastases, recurrence, and survival were examined. Results: Occult neck metastases occurred in 34 percent of patients. Tumor thickness was the only independent predictor of occult metastases, with thin (≤5 mm) and thick (>5 mm) tumors having a 10 percent and 46 percent incidence of regional disease, respectively (P = 0.001). Nodal metastases and perineural invasion were significant predictors of survival. Conclusion: Patients with thick tumors are at high risk of nodal metastases and are likely to benefit from elective neck dissection. Comprehensive neck dissection should be considered in advanced primary disease. Significance: Tumor thickness is the most important predictor of occult regional metastases in oral cavity cancer.