Chronic obstructive pulmonary disease (COPD) can be diagnosed when the FEV1/FVC ratio is below 70%, according to Global initiative for chronic obstructive lung disease. However, there is a risk of over-diagnosis when this diagnostic threshold is applied among the elderly.Aims:T o contribute to the discussion about the criteria for diagnosing COPD, by describing the lung function in a population aged 60 years or more, and in particular the changes in the mean and 5% percentile of the FEV1/FVC ratio with increasing age.Subjects and methods:A cross sectional population based study was performed in the city of TromsØ, Norway, in 2001–2002. Spirometry was done in 4102 people 60 years and older (54.6% women).Results:A drop in FEV1% predicted and FEV1/FVC ratio associated with smoking and increasing age was found. The frequency of FEV1/FVC ratio <70% increased steeply by increasing age and was about 20% in never smoking women and men aged 75 years and more. The 5% percentile of the FEV1/FVC ratio dropped more rapidly by increasing age in healthy never smokers than could be expected from currently used reference values.Conclusions:Adjustments of the GOLD criteria for diagnosing COPD are needed, and FEV1/FVC ratios down to 65 and 60 % should be regarded as normal when aged 70 and 80 years or more, respectively.Conflict of interest and fundingThere are no conflicts of interest.