Diabetes mellitus and coronary artery disease (CAD) commonly coexist, and thus effective, cost-effective management strategies are needed. Intensive management of diabetes has been shown to increase medical costs while yielding better outcomes, with an acceptable cost-effectiveness ratio of <50,000 dollars per life-year added. On the basis of clinical trial findings in the 1970s and 1980s, coronary bypass surgery was cost-effective compared with medical therapy in the treatment of extensive CAD. Few trials have compared angioplasty with medical therapy, and its cost-effectiveness is not well established. The economic outcomes of contemporary coronary revascularization, especially angioplasty, compared with contemporary medical therapy must be evaluated. The Bypass Angioplasty Revascularization Investigation 2 Diabetes (BARI 2D) trial will collect extensive economic data and examine the cost-effectiveness of alternative strategies to manage diabetes and CAD in patients with both disorders.