Cancer of the nasal cavity and paranasal sinuses is a rare disease. The many different histologies and sites make the management of this disease a challenge. The current report from the Danish Society for Head and Neck Oncology comprises a joint analysis of five retrospective series covering the entire country, with 315 patients seen in the 10-year period from 1 January 1982 to 31 December 1991. Tumour sites were nasal cavity (n = 156), maxillary sinus (n = 139), ethmoid sinus (n = 14), sphenoid sinus (n = 5) and frontal sinus (one case). The most common histologies included squamous cell carcinoma (126 cases), adenocarcinoma (41 cases), malignant melanoma (38 cases) and malignant lymphoma (34 cases). A total of 284 patients (90%) received treatment with curative intent; most of these patients were treated with radiotherapy, either alone (120 patients) or in combination with surgery (111 patients). There was no significant difference between the five centres in disease specific survival and overall survival. The results showed that histology, localization and nodal involvement were significant prognostic factors for locoregional control and survival. Patients with squamous cell carcinoma had a significantly poorer prognosis compared with patients with adenocarcinoma. However, a Cox multivariate analysis revealed that this was likely the result of tumour localization, as most adenocarcinomas were in the nasal cavity. The experience from this data collection has inspired the Danish Society for Head and Neck Oncology to arrange common data registration of several other clinical head and neck series. In the future, the Society plans to expand this activity further.