This study compares the quality of life of a community sample of people with asthma in South Australia, using population norms, people suffering from other chronic diseases, and a sample of asthma patients from two hospital clinics. A representative population survey was performed by trained interviewers in spring 1995 of 3001 respondents aged > or = 15 years. A physician's diagnosis of current asthma was reported by 299 (9.9%). The hospital clinic sample had a physician's diagnosis and lung function evidence of asthma (n = 293). All completed the SF-36 health survey. Standardized SF-36 scores, adjusted for age, sex, and social class, were significantly lower for respondents with asthma, compared with population norms, across all subscales of the SF-36 (p < 0.05). Physical component summary (PCS) and mental component summary (MCS) scores were not significantly different in people in the community sample with asthma from scores in people with diabetes and arthritis. PCS and MCS scores did not differ for those with similar symptom frequency in the community and hospital asthma samples, except that hospital patients with frequent symptoms had significantly lower MCS scores (p < 0.01). Asthma has a major impact on the health-related quality of life in the community, comparable to other chronic diseases. The SF-36 performs uniformly in asthma in different situations.