The supraglottic larynx has a rich lymphatic network that places patients with supraglottic laryngeal carcinomas at high risk for early dissemination of the disease into the cervical lymphatics. Therefore, elective neck treatment of clinically N0 neck in patients with supraglottic carcinomas is widely accepted as a standard approach. However, the issue whether elective neck treatment should routinely be directed on both sides of the neck is still controversial. The present study is aimed at determining whether T2-T4 stage supraglottic carcinomas require bilateral neck dissection in the management of N0 necks. We designed a prospective study on 72 patients with N0 supraglottic laryngeal carcinoma. Patients were divided into three groups according to the site and extension of the primary tumors. Group I consisted of 21 patients with lateralized (clear lateral) lesion reaching but not crossing the midline. Group II comprised 25 patients with cancer largely involving one side and crossing to the midline. Group III included 26 patients with carcinoma equally involving both sides of the larynx or growth into the midline larynx. All patients underwent bilateral lateral neck dissection in conjunction with various types of laryngectomies selected to the status of the primary. Of the 72 patients, 16 were found to have occult regional metastases in pathologic examination (9 pN1, 4 pN2b, 3 pN2c). The prevalence of occult metastases proportionally increased with T stage from 8.3 to 22.7 and 31.2%, respectively, for T2, T3 and T4. Bilateral neck metastases were found in 2 of 26 patients (7.7%) with central lesions. There was only one patient (4%) with both ipsilateral and contralateral lymph node metastasis in group II. None of the 21 patients with lateral lesion (group I) had contralateral neck metastasis. Routine bilateral elective neck dissection may not be a part of the surgical procedure in all supraglottic laryngeal carcinoma patients. Bilateral neck dissection should be preferred for cases with central tumors and lateral tumors with positive nodes in the ipsilateral side of the neck.