It has been suggested that percutaneous coronary intervention (PCI) by high-volume operators may be associated with better outcomes. However, the relation between operator and outcome is confounded by hospital caseloads of PCI, with busier hospitals generally having better outcomes. We assessed the effect of operator characteristics (volume of PCI, years in practice, and board certification status) on contemporary outcomes of PCI in a busy center with high-volume operators. Between 1999 and 2001, 12,293 PCIs were performed at our center by 28 interventionalists. Patients' clinical risk was assessed with the previously validated Beaumont PCI Risk Score. Operators were classified as producing low, medium, or high volume (tertiles of annual PCI volume < or =92, 93 to 140, or >140, respectively), as less, medium, or great experience (tertiles of years in practice < or =8, 9 to 14, or >14 years, respectively), and board certified (68%) or not. In-hospital death rate and a composite end point (death, coronary artery bypass graft surgery, myocardial infarction, or stroke) occurred in 0.99% and 2.59% of patients, respectively. Operator volume, experience, and board certification showed no univariate or multivariate relation with the study end points. The Beaumont PCI Risk Score showed a strong independent relation with in-hospital death rate (adjusted odds ratio 1.37, 95% confidence interval 1.31 to 1.43, p <0.0001) and composite end point (odds ratio 1.19, 95% confidence interval 1.16 to 1.22, p <0.0001). We conclude that, in contemporary PCI practice at a large center with high-volume operators, in-hospital outcomes are not affected by operator volume, experience, or board certification. Rather, patients' clinical risk score is the overriding determinant of clinical outcomes. Our findings emphasize the power of a well-organized high-volume system to minimize the impact of operator factors on outcomes of PCI.