Objective. Emotional distress has been related to clinical events in patients with coronary artery disease, but the influence of positive affect (i.e. mood states such as activity, joy and cheerfulness) has received little attention. Therefore, we wanted to investigate the role of positive affect on clinical outcome after percutaneous coronary intervention (PCI) with stent implantation in these patients. Design. Prospective follow-up study. At baseline, patients from the Rapamycin-Eluting Stent Evaluated At Rotterdam Cardiology Hospital (RESEARCH) registry completed measures of positive affect, depression and anxiety post-PCI. Patients with reduced positive affect scored 1 SD below the mean score. Setting. University Hospital; Thoraxcenter of the Department of Cardiology. Subjects. 874 patients (72% men; 62.2 +/- 10.9 years) from the RESEARCH registry. Main outcome measure. Death or myocardial infarction (MI) 2 years post-PCI. Results. At follow-up, there were 52 clinical events (deaths n = 27, MIs n = 25). Reduced positive affect and depression/anxiety were associated with poor prognosis, but reduced positive affect was the only independent predictor of events. The incidence of death/MI in adequate versus reduced positive affect patients was 4% (29/663) vs. 11% (23/211); HR = 2.55 (95% CI 1.46-4.34, P = 0.001), adjusting for clinical variables. Reduced positive affect and diabetes were independent prognostic factors, and patients with one (HR = 2.84, 95% CI 1.58-5.10) or both (HR = 5.61, 95% CI 2.25-13.99) of these factors had a higher risk when compared with nondiabetic patients with adequate positive affect, P <= 0.003. Conclusions. Reduced positive affect independently predicted death/MI following stent implantation, and improved risk stratification above and beyond diabetes.