In recent years there has been a heightened awareness of the importance of inflammatory processes in both coronary artery disease and cardiopulmonary bypass. Leukotrienes are a group of proinflammatory metabolites of arachidonic acid whose biologic effects have led to the postulation that they have a role in a broad number of functions and inflammatory disease processes. There is evidence to suggest a putative role of leukotrienes in coronary artery disease. In particular, the cysteinyl leukotrienes are potent vasoconstrictors of coronary arteries and can be generated by cell types known to be found in atherosclerotic arteries and that can participate in the process of atherosclerosis. In addition, leukotrienes are elevated in patients with cardiac ischemia, and following coronary artery bypass graft surgery, suggesting that the leukotrienes as well as other inflammatory mediators participate in the pathogenesis of cardiac ischemic syndromes. Understanding of the role of mediators involved in coronary heart disease and cardiopulmonary bypass could be of great value in managing these patients as well as developing new strategies for treatment.