The aim of this study was to identify possible risk indicators for pneumonia leading to death and hospitalization in the general population. We followed 6,158 men and 7,265 women aged 30-70 years, who participated in the Copenhagen City Heart Study, a prospective population study, for 12 years with regard to mortality and hospital admissions for pneumonia. A total of 260 deaths with pneumonia as main or contributory death cause had occurred, and 405 subjects had been admitted to hospital at least once because of pneumonia. Mortality and hospitalization were analysed by multivariate Cox regression models. In addition to increasing age, forced expiratory volume in one second (FEV1) was strongly and consistently related to both pneumonia related mortality and hospitalization. Women with FEV1 < 60% predicted had a relative risk of 5.7 (95% confidence interval: 2.9-11) and 3.6 (2.1-6.4) for death and hospitalization, respectively, when compared with women with FEV1 > or = 100% predicted. Similar, although lower, relative risks were observed in men. Other significant risk indicators for hospitalization were: self-reported asthma (women), mucus hypersecretion (women and men), history of stroke (men) and smoking (women). We conclude that, in addition to age, reduced FEV1 is the most important risk indicator for severe pneumonia.