Additions to the OPTN waiting list decreased in 2003 for all organs except kidney. On November 30, 2004 there were 95,598 registrations on the combined UNOS waiting list. Of these, 67% were awaiting kidney transplantation and 18% were awaiting liver transplantation. The majority of patients on the UNOS waiting list on November 30, 2004 were blood type O (51%), male (57%) and awaiting their first transplant (87%). Despite lengthy waiting times, the percentage transplanted within one year following listing increased over the past 3 years for all organs except heart and kidney. A substantial increase in the percentage of heart-lung candidates transplanted within one year was observed in 2003. Blood type and medical urgency had a significant impact upon percent transplanted within one year of listing for most organ types. Patients awaiting heart, liver, pancreas and intestine transplants had the highest probability of receiving a transplant within one year. Death rates have remained fairly stable over time; however, cause of death while waiting for a transplant varied with organ type. Death due to cardiovascular reasons was the most common cause of death for heart and kidney candidates who were on the UNOS waiting list, while multiple organ failure was the most common cause of death for liver and intestinal candidates who were on the UNOS waiting list.