The value of early detection and treatment of chronic obstructive pulmonary disease (COPD) is currently unknown. We assessed the cost effectiveness of primary care-based case detection strategies for COPD. A previously validated discrete event simulation model of the general population of COPD patients in Canada was used to assess the cost effectiveness of 16 case detection strategies. In these strategies, eligible patients (based on age, smoking history, or symptoms) received the COPD Diagnostic Questionnaire (CDQ) or screening spirometry, at 3- or 5-year intervals, during routine visits to a primary care physician. Newly diagnosed patients received treatment for smoking cessation and guideline-based inhaler pharmacotherapy. Analyses were conducted over a 20-year time horizon from the healthcare payer perspective. Costs are in 2019 Canadian dollars ($). Key treatment parameters were varied in one-way sensitivity analysis. Compared to no case detection, all 16 case detection scenarios had an incremental cost-effectiveness ratio (ICER) below $50,000/QALY gained. In the most efficient scenario, all patients aged ≥ 40years received the CDQ at 3-year intervals. This scenario was associated with an incremental cost of $287 and incremental effectiveness of 0.015 QALYs per eligible patient over the 20-year time horizon, resulting in an ICER of $19,632/QALY compared to no case detection. Results were most sensitive to the impact of treatment on the symptoms of newly diagnosed patients. Primary care-based case detection programs for COPD are likely to be cost effective if there is adherence to best-practice recommendations for treatment, which can alleviate symptoms in newly diagnosed patients.