Background: Associations have been reported between irritable bowel syndrome (IBS) and asthma. Aims: To explore the inter-relations between these conditions in a general population sample. Subjects: A randomly selected community sample of 5492 adults. Methods: All of the subjects were invited for a medical interview. Those subjects suspected to have either asthma and/or IBS underwent spirometry with post-bronchodilator test if indicated. The labeling of subjects as having IBS was based on Rome 11 criteria. Results: 4762 subjects agreed to take part (86.7% response). Prevalence rates for IBS, and currently active asthma were 7.1% and 3.8%, respectively. Logistic regression showed independent associations between IBS and most asthma symptom categories. There was no significant independent association between IBS and chronic bronchitis. The odds ratio with 95% confidence interval (CI) for IBS and current asthma was 1.79 (1.06-3.03). Conclusions: These observations indicate the necessity of further community-based studies to elucidate the possible common pathogenic mechanisms involved in two disease entities. (c) 2005 Elsevier Ltd. All rights reserved.