Objectives: The purpose of this study was to evaluate the incidence and predictive factors of contralateral occult lymph node metastasis in oral cavity squamous cell carcinomas to form a rational basis for elective contralateral neck management. Materials and Methods: We performed a retrospective analysis of 66 N0-2 oral cavity cancer patients undergoing elective neck dissection for contralateral clinically negative necks from 1991 to 2003. Results: Clinically negative but pathologically positive contralateral lymph nodes occurred in 11%(7 of 66) . Of the 11 cases with a clinically ipsilateral node positive neck, contralateral occult lymph node metastases developed in 36%(4 of 10, in contrast with 5%(3/55) in the cases with clinically ipsilateral node negative necks(p<0.05). Based on the clinical staging of the tumor, 8%(3 of 37) of the cases showed lymph node metastases in T2 tumors, 25%(2 of 8) in T3, and 18%(2 of 11) in T4. None of the T1 tumors(10 cases) had pathologically positive lymph nodes. The rate of contralateral occult neck metastasis was significantly higher in advanced stage cases and those crossing the midline, compared to early stage or unilateral lesions(p<0.05). Patients with no evidence of contralateral nodal cancer had significantly improved disease-specific survival over patients with any pathologically positive nodes(5-year disease-specific survival rate was 79% vs. 43%, p<0.05). Conclusion: The risk of contralateral occult neck involvement in the oral cavity squamous cell carcinomas above the T3 stage or those crossing the midline with unilateral metastases was high. Therefore, we advocate an elective contralateral neck treatment with surgery or radiotherapy in oral cavity squamous cell carcinoma patients with ipsilateral node metastases or tumors that are greater than stage T3 or crossing the midline.