The clinical significance and subsequent management of the various types of coronary artery anomalies (CAAs) are different, as is the relationship to sudden death, coronary artery disease, and myocardial ischemia. A practical global classification based on clinical significance has not yet been proposed. This retrospective study was aimed at evaluating the current clinical significance of CAAs and the effectiveness of a clinical-significance-based classification. In a single-center retrospective study at a public hospital, a review of the last 5,100 coronary angiographies was performed in order to select patients with CAAs. The CAAs were classified into 4 categories on the basis of a literature review according to angiographic appearance and clinical significance: benign (class I); relevant-associated with fixed myocardial ischemia (class II); severe-related to sudden death (class III); and critical-associated with superimposed coronary artery disease (CAD) (class IV). Clinical and instrumental records of the selected patients were reviewed as well as the occurrence of cardiovascular events from the date of diagnosis to July 2002. Sixty-two patients (1.2%, women/men 20/42, mean age 65.3 +/-10.6 years) had CAA on coronary angiography. From the above-described classification, 40 patients were categorized in class I (64.5%), 9 in class II (14.5%), 7 in class III (11.3%), and 6 in class IV (9.7%). During the follow-up (mean duration 60.4 +/-12.3 months) most cardiovascular events and death occurred in class III and IV patients (71.3% and 100% respectively). A high correlation was found between significance level and percentage of patients with cardiovascular events (r = 0.99). Actuarial survival at 5 years was 82.9%. CAAs can be practically classified on the basis of clinical presentation and significance. This clinical classification may be useful in managing patients with CAA and personalizing their follow-up and therapeutic options according to their class and case histories.