Tobacco and alcohol abuse are the major known risk factors for the development of squamous cell head and neck cancer (SCHNC). Information about this disease in nonsmokers, however, is limited. We retrospectively studied a group of 59 tobacco nonusers with SCHNC, diagnosed since 1986 at the Cleveland Clinic Foundation (CCF). Two objectives were defined: (a) to characterize this nonsmoking population of patients and identify any significant differences compared with a control population consisting of all patients diagnosed with SCHNC at the CCF between 1986 and 1993 and (b) to determine the prevalence of exposure to environmental tobacco smoke in this nonsmoking group of patients with SCHNC and compare it with the environmental tobacco-smoke exposure in a second, control population of non-SCHNC, nonsmoking patients matched for age, race, sex, and alcohol use. The group of nonsmoking patients with SCHNC was notable for only rare alcohol abuse, a preponderance of whites, and relatively fewer laryngeal primary tumors. There were significantly more women and more tongue primaries. When compared with the control population without cancer, the nonsmoking patients had a significantly higher risk of exposure to environmental tobacco smoke both in the home and in the workplace. We conclude that the tobacco nonuser who develops SCHNC is likely to be female and white and to have a primary tongue cancer. A significant association with environmental tobacco smoke exposure is suggested by our data.