Crossed double internal mammary (IMA)-coronary artery grafts (the left to the left anterior descending artery [LAD], the right to a diagonal or marginal coronary branch) were used without mortality and with excellent functional results in 36 patients requiring separate grafts to these vessels (22% of patients undergoing coronary revascularization). Flows were 70 +/- 9 ml/min in the left and 50 +/- 7 ml/min in the right IMA, respectively. All revisualized grafts remained patient. The location and direction of the LAD and of diagonal and marginal branches allow excellent alignment of these shorter and wider double IMA grafts. The left IMA is the graft of choice for the LAD, and the right IMA is the choice for a high diagonal or early arising marginal branch that requires an additional separate graft. The right IMA is not satisfactory for right coronary or LAD bypass.