O465 Aims: The lack of sufficient suitable organs has long been identified as a principle constraint to the benefits of solid organ transplantation. Considerable international variation in donation rates exists. Further, it is becoming increasingly apparent that there is a large pool of potential but unprocured deceased organ donors. We estimated the additional life-year benefit available from unprocured potential donors in 22 countries with active transplant programs on three continents including Europe, North America, and Australia. Methods: Using data describing the characteristics and outcomes of patients wait-listed for transplanted in the United States between 1995 and 2002 from the Scientific Registry of Transplant Recipients, multivariate models designed to assess the total benefit in life-years produced by the organs transplanted from an average deceased organ donor were constructed. Patient survival functions for wait-listed and transplanted outcomes were estimated with proportional-hazards regression models and projected through 40 years post-transplant for heart, liver, lung, kidney, kidney-pancreas, and pancreas transplantation. The average life-year benefit of a transplant to a recipient is the area between the organ specific transplant and wait-list survival functions. The life-year benefit of a deceased organ donor is the sum of organ specific recipient benefits adjusting for the average utilization of each type of organ per donor. National “donation efficiency indices” were estimated by calculating the ratio of the number of deceased organ donors in 2000 to the annual number of deaths due to cerebrovascular accidents and motor vehicle accidents within each country. Countries were benchmarked first, against Spain’s donation efficiency index, the highest observed, and second, against a donor efficiency index assuming procurement of 100% of the potential donors recently estimated for the United States from records of in-hospital circumstances of death. Results: The average deceased organ donor provides 30.8 additional life-years to the recipients of his or her organs. 14,000 deceased organ donors were procured in the studied countries in 2000, providing an expected 430,000 additional life-years to transplant recipients. An additional 7,500 deceased donors, and therefore 230,000 additional life-years, would have been available if all studied countries had donor efficiency indices equal to Spain. An additional 35,000 deceased donors and 1,080,000 additional life-years would have been available if all studied countries’ donor efficiency indices equalled an index based upon the estimated deceased organ donor potential in the United States. Conclusions: The greatest modifiable limitation to the benefits of solid organ transplantation is the conversion of potential deceased organ donors into actual deceased organ donors. The realized overall life-year benefits of transplantation may be as little as 30% of the potential in the 22 countries studied here. While it is unclear how much of the currently unprocured pool can be converted into donors, tremendous additional benefits are available from transplantation if more of the potential could be tapped. Therefore, expanding deceased organ donation deserves the greatly increased attention and effort of both the transplant community and society.