Objectives Bleeding into the chest is a major cause of blood transfusion and adverse outcomes following cardiac surgery. The authors investigated predictors of bleeding following cardiac surgery to identify potentially correctable factors. Design Data were retrieved from the medical records of patients undergoing cardiac surgery over the period of 2002 to 2008. Multivariate analysis was used to identify the independent predictors of chest tube drainage. Setting Tertiary hospital. Participants Two thousand five hundred seventy-five patients. Interventions Cardiac surgery. Results The individual operating surgeon was independently associated with the extent of chest tube drainage. Other independent factors included internal mammary artery grafting, cardiopulmonary bypass time, urgency of surgery, tricuspid valve surgery, redo surgery, left ventricular impairment, male gender, lower body mass index and higher preoperative hemoglobin levels. Both a history of diabetes and administration of aprotinin were associated with reduced levels of chest tube drainage. Conclusions The individual operating surgeon was an independent predictor of the extent of chest tube drainage. Attention to surgeon-specific factors offers the possibility of reduced bleeding, fewer transfusions, and improved patient outcomes.