Dr. Samuel L. Kountz (October 30, 1930 – December 23, 1981) was an African-American kidney transplantation surgeon from Lexa, Arkansas. He was most distinguished for his pioneering work in the field of kidney transplantations, and in research, discoveries, and inventions in Renal Science. In 1961, while working with Dr. Roy Cohn at the Stanford University Medical Center, he performed the first successful Kidney transplant between humans who were not identical twins. Six years later, he and a team of researchers at the University of California, San Francisco, developed the prototype for the Belzer kidney perfusion machine, a device that can preserve kidneys for up to 50 hours from the time they are taken from a donor’s body. It is now standard equipment in hospitals and research laboratories around the world.