Traditionally, the severity of chronic obstructive pulmonary disease (COPD) and effectiveness of interventions have been determined using measures of lung function. However, a relatively small reduction or change in lung function - such as those observed in mild to moderate COPD - may not always reflect the impact of the disease or intervention on patients' physical and psychological well-being. This paper examines the utility of various outcome measures that can be used in primary care to monitor and manage COPD. In particular, it demonstrates the importance of measuring patient-centred outcomes, such as health-related quality of life and exacerbations, which may reflect more accurately the effects of the disease and treatment on patients' everyday lives. Recent large-scale clinical trials of budesonide/formoterol and fluticasone/salmeterol combination therapies and tiotropium have utilised these outcome measures to show the significant benefits these treatments bestow to patients in the presence of relatively modest gains in lung function.