While preoperative aspirin (ASA) therapy does not increase allogeneic transfusion in elective primary coronary artery bypass grafting (CABG) operations, the impact of ASA consumption on transfusion in cardiac operations with greater risk of bleeding has not been investigated. We examined the influence of ASA consumption on mediastinal drainage and allogenic transfusion in 317 patients undergoing reoperative CABG surgery. Patients receiving ASA or ASA containing medications within 7 days preoperatively (n = 215) had similar perioperative characteristics but were older and had smaller red cell volumes than control patients not receiving ASA (n = 102). All patients received aminocaproic acid, but autotransfusion of mediastinal blood or platelet rich plasma, aprotinin, or desmopressin were not used. No significant differences were observed between ASA and control groups with respect to postoperative hematocrit, mediastinal drainage, frequency of reexploration for excessive bleeding, amount of allogeneic packed red blood cell, fresh frozen plasma, platelet concentrate or cryoprecipitate transfusion, or the fraction of patients receiving any allogeneic blood product. There was no difference in mediastinal drainage when stratified by timing of most recent ASA ingestion. Multiple linear regression identified duration of cardiopulmonary bypass (CPB), internal mammary artery harvesting, chronic preoperative steroid therapy and use of an intraaortic balloon pump (IABP) as significant predictors of mediastinal drainage. Logistic regression demonstrated that female gender, prolonged duration of CPB, advanced age, use of IABP, and a negative history of smoking were significant independent predictors of blood product transfusion. There was no significant interaction of preoperative heparin therapy with ASA on transfusion demonstrated by univariate or multivariate analyses. These results indicate that preoperative ASA ingestion is not an important determinant of mediastinal drainage or allogeneic transfusion, even after repeat CABG operations, and that surgical and patient characteristics are more important predictors of these outcomes.