OBJECTIVES: To assess the severity of obstructive airways disease using a postal questionnaire and to examine correlations between healthcare utilisation/cost and disease severity. METHOD: A postal survey was conducted among general practice patients who were defined as likely to have obstructive airways disease on the basis of a previous postal respiratory questionnaire. The six-item severity questionnaire was based on the GINA guidelines and considered symptom frequency and intensity. Individuals were categorised into one of four severity groups. Healthcare utilisation events and cost of care (over six months) for the four groups were compared. RESULTS: Disease was classified as intermittent in 52.9%, mild persistent in 27.2%, moderate persistent in 12.9% and severe persistent in 7.1%. The six items of the severity questionnaire were strongly correlated (Spearman’s rho 0.56-0.80, p<0.001 throughout), suggesting measurement of a single construct. Severity classification using the questionnaire was significantly correlated with healthcare utilisation and cost. In general, those categorised as having the most severe disease had at least double the healthcare utilisation of those with least severe disease, with mean total cost over 6 months increasing from £428.55 (least severe) to £1431.50 (most severe) (p<0.001 for correlation). CONCLUSIONS: This short postal questionnaire will provide a useful categorisation of obstructive airways disease severity in large scale epidemiological studies.