The 8th American Transplant Congress (ATC) was held at the Toronto Convention Center in Toronto, Canada from May 31 to June 4, 2008. The conference attracted more than 3500 physicians, pharmacists, nurses, technologists, basic researchers and social workers in the field of transplantation from all over the world. The following is an overview of the conference in terms of rational immunosuppression and monitoring after organ transplantation. Inadequate immunosuppression can lead to numerous hazards and adverse outcomes for patients and grafts after transplantation, including acute rejection (AR), subclinical and chronic rejection, resulting in structural and functional graft damage, loss of graft function, sensitization of the recipient, and difficulty in re-transplantation and even death of the recipient. 1. Acute rejection Studies have shown that with the use of newer immunosuppressive agents, the incidence of AR between 0 and 6 months, 6 and 12 months, and 12 and 24 months after transplantation was significantly reduced between 1995 and 2000. No AR or only mild AR occurred within 72 months after transplantation [Banff grade I and increased serum creatinine (SCr) from baseline.