In an effort to assure quality and contain costs, several major private health insurers now restrict payment of transplantation procedures to designated programs, often referred to as centers of excellence. These insurers underwrite coverage for over 100 million people. Few transplantation programs meet the criteria set forth by insurers, thus raising concerns about patient access to care. The criteria being used by five private insurers and Medicare were obtained and reviewed. Insurers now designate kidney, heart, liver, heart-lung, pancreas, and bone marrow transplant programs based upon total annual transplant volume as well as one- and two-year patient and graft survival rates. Transplant center criteria vary according to procedure and type of recipient (i.e., pediatric vs. adult). Most insurers require hospitals to perform a minimum of at least 6, and up to 50 procedures annually. Expected one-year patient survival rates may exceed 90% and are often higher than 80%, although standards are usually lower for heart-lung and bone marrow transplantation. In addition, if centers meet the minimum volume and outcome criteria, insurers expect transplant centers to discount per procedure changes by as much as 25%. Patients are often offered incentives to use designated centers with insurers frequently paying travel costs and reducing or waiving copayment amounts. The designation of transplant programs by third-party payers has merit, although program volume requirements may have less validity than individual transplant surgeon and physician experience. Other problems are also apparent. For example, discount pricing is suspect, given the lack of data on actual transplant procedure costs. Also, some insurers intend to regionalize transplant programs, thus unnecessarily limiting patient access to care. Alternatively, the concentration of transplant activity at a smaller number of centers may enhance research opportunities. Nonetheless, transplant professionals, hospital administrators, and patient advocates remain wary of insurer objectives. There is concern that the designation of centers is simply another method by which insurers can avoid paying for transplants.