Responsiveness of neck nodes to induction chemotherapy often differs from that of the primary tumour. We have conducted a retrospective study to evaluate the results of treating the neck in a cohort of 350 patients with locally advanced (T3-4) head and neck carcinomas treated with radiation therapy at the primary location of the tumour after induction chemotherapy. One hundred and thirty-nine patients (40%) did not have neck nodes on diagnosis (N0). The treatment of the neck included surgery in 65 patients. Neck dissections were carried out before radiotherapy in 37 patients and after radiotherapy in 28 patients. The frequency of neck treatment failure was 24%. There was a tendency to better neck control when treatment included neck dissection, independently of the neck stage or response to chemotherapy. This tendency was statistically significant in patients with an advanced regional tumour (N2-3) who did not achieve a complete regional response after chemotherapy. In a multivariate analysis the variables that were related to the regional failure were the relapse of the tumour at the primary site, the neck stage (N), the type of treatment used in the neck, and the grade of regional response after induction chemotherapy. Our results lead us to suggest that after induction chemotherapy neck surgery is advisable in all cases with advanced regional disease (N2-3), independently of the grade of response achieved after induction chemotherapy, and is also advisable in N1 patients in whom induction chemotherapy does not achieve a complete response.