Anesthesiologists and surgeons have focused on the problems of hypocoagulability and resulting hemorrhage after cardiopulmonary bypass. Recent work in endothelial cell biology has demonstrated that the interaction of inflammatory processes and coagulation dysfunction with the endothelium may contribute to either hypocoagulability (bleeding) or hypercoagulability (thrombosis). New work with endothelial cell function and intracellular signaling of procoagulant responses may allow for unique therapeutic interventions in the future.