Increased awareness of the risks of blood-borne infections has recently led to profound changes in the practice of transfusion medicine. These changes include, among others, the development of guidelines by the American College of Physicians (ACP) for transfusion. Although the incidence and predictors of vascular complications of percutaneous interventions have been well defined, there are currently no data on frequency, risk factors, and appropriateness of blood transfusions. We performed a retrospective analysis of 628 consecutive percutaneous coronary revascularization procedures. Predictors of blood transfusion were identified using multivariate logistic regression analysis. Appropriateness of transfusions was determined using modified ACP guidelines. Transfusions were administered after 8.9% of interventions (56 of 628). Multivariate analysis identified age >70 years, female gender, procedure duration, coronary stenting, acute myocardial infarction, postprocedural use of heparin and intra-aortic balloon pump placement as independent predictors of blood transfusions (all p <0.05). According to the ACP guidelines, 36 of 56 patients (64%) received transfusions inappropriately. Transfusion reactions (fever) occurred in 10% of patients who received tranfusions appropriately and in 5% of patients who received tranfusions inappropriately. The estimated additional costs per procedure related to transfusions were $551 and $419, respectively. In conclusion, unnecessary transfusions were performed frequently after percutaneous coronary interventions. Application of available guidelines could reduce the number of unnecessary transfusions, thus avoiding exposure of patients to additional risks and reducing procedural costs.