The relevance of benign congenital coronary anomalies (CAAs) in the atherosclerotic process is still confused despite the number of single reports of coronary artery disease in CAAs. The present study is aimed at assessing the role of CAAs on the progression of coronary artery disease (CAD). A review of the last 15,000 coronary angiographies was performed to select patients with CAAs, and they were divided into 2 groups on the basis of the presence (group I) or the absence (group II) of CAD. Clinical and instrumental records of the selected patients were reviewed and the numbers of cardiovascular events for each group (acute myocardial infarct, unstable angina, silent ischemia, bypass or percutaneous transluminal coronary angioplasty (PTCA) interventions, and cardiovascular death) were recorded from the date of diagnosis to July 2002. Group I (22 patients, mean age 64.1 +/- 9.1 years, F/M = 10/12) and group II (17 patients, mean age 66.5 +/- 10.6 years, F/M = 7/10) were similar for age and ejection fraction values. The presence of risk factors was statistically higher in group I. The number of patients with cardiovascular events was significantly higher in group I: 50% (11 patients) in group I vs 12% (2 patients) in group II, p<0.05). Repeated coronary angiography in 8/11 patients of group I and in the 2 patients of group II confirmed that the causes of the events were precedent atherosclerotic lesions in 7 patients and newly developed lesions in 3. At a mean follow-up of 60.4 +/- 12.3 months, mean actuarial survival was lower in group I than in group II (74.8% vs 100%, p=0.045), whereas mean event-free survival was 41.7% in group I and 88.7% in group II (p=0.02). Benign CAAs do not seem per se to be an accelerating factor for coronary atherosclerosis development in patients with no or few classical risk factors.