Purpose of review: Chronic rhinosinusitis (CRS) is a common health problem with impact on general health and significant medical costs. To date, no pan-European epidemiological study has been undertaken and prevalence data for Europe were unavailable. GA(2)LEN network of excellence has developed a questionnaire, the GA(2)LEN survey to assess the presence of CRS and its association with asthma in epidemiological studies using the European Position Paper on Rhinosinusitis and nasal Polyps (EP3OS) diagnostic criteria. Recently, first data were published and the results are summarized in this review. Recent findings: Information was obtained from 57,128 responders living in 19 centers of 12 countries. The overall prevalence of CRS by EP3OS criteria was 10.9%. CRS was more common in smokers than in nonsmokers. The prevalence of self-reported physician-diagnosed CRS within centers was highly correlated with the prevalence of EP3OS-diagnosed CRS. Symptom-based CRS was significantly associated with positive endoscopy in non-allergic subjects, and with self-reported doctor-diagnosed CRS in all subjects. In all centers, there was a strong association of asthma with CRS at all ages. The association with asthma was stronger in those reporting both CRS and allergic rhinitis. Conclusion: Using the GA(2)LEN survey, a mean prevalence of 10% with a considerable geographical variation in adults in Europe could be demonstrated. Smoking was associated with having CRS in all parts of Europe. Symptom-based definition of CRS, according to the epidemiological part of the EP3OS criteria, was suitable for the assessment of geographic variation in prevalence of CRS. The strong and independent associations between asthma and both allergic rhinitis and CRS are important for better understanding of these conditions and their interdependence and may lead to better management in the future.