BACKGROUND: We have prospectively analyzed the prevalence and distribution of histologic cervical node metastases in laryngeal and hypopharyngeal squamous carcinoma to determine the most appropriate form of neck dissection. METHODS: We have examined specimens from 100 consecutive patients in whom neck dissection was part of the primary treatment of laryngeal and hypopharyngeal carcinoma. Fifty eight patients were treated by unilateral or bilateral selective dissection of levels I to IV +/- VI for N0 disease and 42 by comprehensive dissection for N+ disease. Assessment was by separation of the specimens into node levels at the time of surgery and embedding all the resected material for histologic analysis. RESULTS: Nodal metastases were found in 36% of ipsilateral and 27% of contralateral dissections in the N0 cases. The corresponding prevalences in N+ cases were 90% and 37%, respectively. All metastases in N0 and N1 disease were confined to levels II, III, IV, and VI. Metastases to levels I and V were infrequent even in N+ disease. CONCLUSIONS: Our results support the use of elective dissection of node levels II to IV for N0 laryngeal and hypopharyngeal carcinoma. We suggest the inclusion of level VI nodes for tumors invading the subglottis, pyriform fossa apex, and postcricoid region. The prevalence of bilateral metastases is great enough in midline or bilateral tumors to justify bilateral selective dissection. It is possible that selective neck dissection is also adequate for small palpable metastases, but greater numbers are required to confirm this.