A prospective analysis of overall and cause-specific mortality in subjects with self-reported asthma was undertaken using the data from The Copenhagen City Heart Study. A sample of 13,540 individuals selected from the general population was followed for 17 years. Survival of subjects with self-reported asthma was significantly poorer than that of non-asthmatics, the excess mortality being limited to pulmonary mortality. After statistical adjustment for age, length of school education, and smoking, women with asthma had a 1.7 higher risk of dying than women without asthma. The similar risk for men was 1.5. Inclusion of one-second forced expiratory volume, in % predicted, in the mortality analyses showed that the increased risk of death associated with asthma was mediated mainly through reduced lung function. We conclude that in the general population self-reported asthma is associated with a slight excess of mortality, mainly due to respiratory disease.