Chronic obstructive pulmonary disease (COPD) is an important cause of morbidity and mortality worldwide, yet it remains significantly under-diagnosed. Systematic and opportunistic case-identification efforts in primary care, using questionnaires, careful assessment to identify symptoms, and follow-up spirometry, might improve diagnosis rates and enable earlier detection and management of COPD. The aims of spirometry performed for case-identification purposes are to exclude those patients with symptoms but normal lung function and identify those who require more complete investigation for COPD, including 'diagnostic standard' spirometry. Among patients with a confirmed diagnosis of COPD, spirometry monitoring is useful in identifying those with rapid deterioration in lung function who require further assessment. Spirometry in primary care can also support patient education and may encourage smoking cessation and treatment adherence.