OBJECTIVE: Comparable population-based data exist at the European level for asthma but not for chronic obstructive pulmonary disease. Data from the World Health Organization's Large Analysis and Review of European Housing and Health Status Study conducted in random samples from eight European cities were used 1) to describe the prevalence of chronic bronchitis and emphysema (CBE) and asthma according to socio-demography, addictions, physical activities and body mass index; and 2) to identify the co-morbidities of these respiratory diseases. DESIGN: A total of 6915 adults filled out a standardised questionnaire on health outcomes, including major respiratory diseases and individual characteristics. RESULTS: Data showed that in the year preceding the survey, 3.3% of individuals had been diagnosed or treated for asthma and 6.2% for CBE. One per cent suffered simultaneously from both. Large variations were observed between cities. Physical activities and never smoking were inversely associated with CBE, independently of socio-cultural differences between the eight cities. Furthermore, both asthma and CBE were significantly related to several non-respiratory diseases, after adjustment for potential confounders. CONCLUSION: Population-based data from eight European cities show that there is a link between chronic respiratory diseases and various non-respiratory co-morbidities that needs further investigation.