During a recent 5-year period, 115 patients had 131 supraomohyoid neck dissections. Eighty-one percent of these procedures were performed for squamous carcinoma. Seventy-nine percent of the primary tumors were located in the oral cavity and 16 percent arose in the oropharynx. Almost 80 percent of the necks dissected for primary squamous carcinoma were clinically N0, and occult nodal disease was discovered in 31 percent of these neck specimens. When the supraomohyoid neck dissection specimen showed no involvement, the overall incidence of treatment failure in the neck at 2-year follow-up was 5 percent. Almost all patients with occult squamous carcinoma in the supraomohyoid neck dissection specimen received postoperative radiotherapy, and the failure rate in the neck was 15 percent. When neck nodes were both clinically and pathologically involved, neck recurrence developed in 29 percent of the patients despite the addition of adequate postoperative radiotherapy. Among those patients with nonsquamous primary tumors and a pathologically negative supraomohyoid neck dissection specimen, there was only one subsequent treatment failure in the neck. Supraomohyoid neck dissection appears to be a valid staging procedure for clinically N0 patients with primary squamous carcinomas located in the oral cavity or oropharynx, with an appropriate yield of occult nodal disease, and infrequent treatment failure in the dissected neck when the supraomohyoid neck dissection specimen is pathologically uninvolved. When nodal disease is clinically obvious, treatment failure is more frequent, even with the addition of postoperative radiotherapy. The role of supraomohyoid neck dissection in this setting deserves further study.