Every day in the United States 17 people die waiting for an organ transplant. The waiting list for organs, which now contains the names of 82,000 people, has more than tripled in the last 10 years. The U.S. policy on who can donate an organ is based both on previous consent of the potential donor and on the consent of the donor's family. This foundation greatly limits the number of potential donors. Spain is the world's leader in providing organs to its population, and the underlying principle of their policy on donors in presumed consent. That is, those people who have not expressly opposed donating their organs are considered eligible for donation. This policy, along with a plan of public education and a strong infrastructure for organ procurement, is what has enhanced their donor rates. Spain is not alone: other countries have seen the benefits of presumed consent and the limits of opt-in systems. The United States must put to use the experiences of these countries to stem the tide of organ shortage and give new life to those desperately awaiting organs.I would like to thank Dr. Philip Lee, Geoffrey Heller, and Dr. Linda Hogle for their invaluable advice on this article.