Aim: To describe the accuracy of diagnosis of COPD from practice nurse (PN) case-finding appointments. Methods: PNs undertook 8+ hours of workshop training in spirometry and case-finding for diagnosis of COPD. Practices invited patients identified as being at risk of COPD (age 40–85, history of smoking, no documented diag- nosis of COPD) to attend a case-finding visit. Quality control of spirometry traces was provided by an expert. For patients identified by PNs as having COPD, spirometry was also performed during home visits by experienced project officers. Results: 36 practices participated; 10 231 invitation letters were sent, 1642 patients (16%) attended a case-finding visit, and 287 (17.5%) were given a diagnosis of COPD by the PN. Of these, 254 (60% male, average age 66 years) were available for project officer visits; 31% were current smokers. The diagnosis of COPD (post-bronchodilator (BD) FEV 1/FVC <0.7), was confirmed in 69% cases. Of these, COPD severity, based on COPD-X criteria, was mild in 45%, moderate in 22% and severe in 2% (borderline in 31%). Patients for whom the diagnosis of COPD was not confirmed were younger (62 vs 68 years, p < 0.0001), and had higher post-BD FEV 1 (83% vs 71% predicted, p < 0.0001) and lower BD reversibility (5.3% vs 9.1%, p = 0.005); they were more likely to have a restrictive pattern than if the diagnosis of COPD was confirmed (40% vs 21%, p = 0.002). Conclusions: Screening in primary care can identify patients with undiag- nosed COPD, but despite training and support, PNs had difficulty interpreting spirometry.