Data on head and neck cancer (HNSCC) is lacking, especially in France. OBJECTIVES: Estimate the costs of inoperable HNSCC patients treated in the private sector and their relationship with patient's medical characteristics. METHODS: We conducted a cohort study in one centre to collect medical data from diagnosis until date of last news or death. Reimbursements of medical fees were obtained from the French Sickness Fund. For the private sector, fee for service rules are applied; as a consequence, all types of health care consumptions could be identified. Consumptions were further linked to treatment phases (initial treatment, follow-up, palliative care) and medical events (chemotherapy, radiotherapy, relapse, adverse event...). Logistic regression was carried out to identify which of the medical characteristics (performance, status, staging, age, localisation) were the main cost drivers. Thirty patients were included and mean duration of follow-up was 13.8 months. Mean total direct costs was estimated at €20,752 per patient, with more than one half for initial radio-chemotherapy (€11,399) phase, around one quarter for follow-up (€4,684) and the same for palliative care (€4,669). 14 patients died during the study and only 9 received palliative care for an average cost per treated patient of €15,563. RESULTS: Type of care distribution varied according to treatment phases with more hospitalisations and medical procedures during initial treatment, more medication during follow-up and more hospitalisation costs during palliative care. Costs of side effects were very high, particularly those associated with mucositis that concerned all patients with a mean cost of €4,582 of which €1,607 for hospitalisation. CONCLUSIONS: Logistic regression highlighted the importance of the nodal staging on the mean total cost per patients and on the daily cost: €35 for AJCC stage III, €55 for stage IVa, €93 for stage IVb patients.