The success of kidney and liver transplantation is hindered by a shortage of organs available for transplantation. Although currently illegal in nearly all parts of the world, a living 'donor' or 'vendor' kidney market has been proposed as a means to reduce or even end this shortage. Physician members of the American Society of Transplantation, the American Society of Transplant Surgeons and the American Association for the Study of Liver Disease were surveyed regarding organ markets for both living kidney and living liver transplantation. The survey queried respondents about their attitudes toward directed living donation, nondirected living donation, the potential legalization of living donor organ markets and the reasons for their support or opposition to organ markets. Partial or completed surveys were returned by 346 of 697 eligible respondents (50%). While virtually all supported or strongly supported directed living donation (98% and 95% for kidney and liver lobes, respectively), the vast majority disagreed or strongly disagreed with the legalization of living donor organ markets (80% for kidneys and 90% for liver lobes). Both those who support and those who oppose a legalized living donor organ market rate risk to the donor among the most important factors to justify their position.