The objective of the present study was to test whether confronting smokers with previously undetected chronic obstructive pulmonary disease (COPD) increases the rate of smoking cessation. In total, 296 smokers with no prior diagnosis of COPD were detected with mild-to-moderate airflow limitation by means of spirometry and randomly allocated to: confrontational counselling by a nurse with nortriptyline for smoking cessation (experimental group); regular counselling by a nurse with nortriptyline (control group 1); or "care as usual" for smoking cessation by the general practitioner (control group 2). Only the experimental group was confronted with their abnormal spirometry (mean forced expiratory volume in one second (FEV1) post-bronchodilator 80.5% predicted, mean FEV1/forced vital capacity post-bronchodilator 62.5%). There was no difference in cotinine-validated prolonged abstinence rate between the experimental group (11.2%) and control group 1 (11.6%) from week 5-52 (odds ratio (OR) 0.96, 95% confidence interval (CI) 0.43-2.18). The abstinence rate was approximately twice as high in the experimental group compared with control group 2 (5.9%), but this difference was not statistically significant (OR 2.02, 95% Cl 0.63-6.46). The present study did not provide evidence that the confrontational approach increases the rate of long-term abstinence from smoking compared with an equally intensive treatment in which smokers were not confronted with spirometry. The high failure rates ( >= 88%) highlight the need for treating tobacco addiction as a chronic relapsing disorder.