Objectives: To contribute to insight in therapeutic safety of selective neck dissections for oral cavity and oropharyngeal cancer with a special focus on the risk of skip metastases. Design: Retrospective data analysis. Setting: Tertiary referral centre. Participants: A total of 291 patients operated for oral cavity or oropharyngeal squamous cell cancer between 1999 and 2004. Main outcome measures: Incidence of skip metastases in both pathologically N0 and N+ necks for oral cavity and oropharyngeal cancer. Results: Of all neck dissections (n = 226) performed for oral cavity cancer, skip metastases to level III or level IV occurred in 14 cases (6%). Ten skip metastases occurred in level III only (10/226 = 4%). Thus, four necks had metastases in level IV, which would not have been removed in case of a Selective neck dissection level I-III (supraomohyoid neck dissection). In case of oropharyngeal cancer, skip metastases to level III or level IV occurred in six of 92 cases (7%). Five skip metastases occurred in level III only (5/92 = 5%). This means that of the necks containing skip metastases, only one neck (1%): had metastases in level IV, which would not have been removed in case of a Selective neck dissection level I-III (Supraomohyoid neck dissection). Conclusions: The question whether level IV should be included in the treatment of N0 and even N1 necks of patients with cancer of the oral cavity and oropharynx cannot be answered by all data available to us now. The fear of skip metastases including level IV does not seem to be justified.