Sinonasal malignancy is a rare disease in which a number of aetiological factors have been implicated. Incidence, site and histological type can vary in different geographical areas which may be due to occupational, social and genetic factors. Relative risk rates have been determined for a number of occupations such as workers with wood, nickel, chrome, chemicals, shoes and textiles though the exact causative agents and mode of action is not entirely clarified. Some non-occupational agents and pathological conditions may also play a role in certain cases. A group of 350 patients with sinonasal malignancy have been reviewed with regard to aetiological factors and more detailed information was obtained in 50 of these patients by questionnaire and interview. Significant exposure to a wide range of known carcinogens was revealed suggesting a possible causative relationship in several unusual histological types.