A seroepidemiological survey, using an indirect immunofluorescence test against Coxiella burnetii (antigenic phase II), was carried out in León province, north-western Spain. A total of 406 serum samples was collected from people (from 15 to more than 65 years old) living in a rural environment during the winter and spring of 1994. The overall prevalence was 40.6%, titres ranged from 1:80 to 1:640, and a titre of 1:80 was encountered among 60.6% of positive samples. A significant higher prevalence was observed among males globally, as well as among those aged 15-44 and 45-64 years old; however, no difference was encountered among males and females older than 64 years. In the same way, a significant higher Q fever prevalence was observed among individuals having occupations related to agriculture and among those having close relationship with animals.