Title: Kidney transplantation
Content: The renal artery of the new kidney, previously branching from the abdominal aorta in the donor, is often connected to the external iliac artery in the recipient. ; The renal vein of the new kidney, previously draining to the inferior vena cava in the donor, is often connected to the external iliac vein in the recipient. In most cases the barely functioning existing kidneys are not removed, as removal has been shown to increase the rates of surgical morbidity. Therefore, the kidney is usually placed in a location different from the original kidney. Often this is in the iliac fossa so it is often necessary to use a different blood supply: The donor ureter is anastomosed with the recipient bladder. In some cases 
Title: Kidney transplantation
Content:  Kidney transplant or renal transplant is the organ transplant of a kidney into a patient with end-stage kidney disease (ESRD). Kidney transplant is typically classified as deceased-donor (formerly known as cadaveric) or living-donor transplantation depending on the source of the donor organ. Living-donor kidney transplants are further characterized as genetically related (living-related) or non-related (living-unrelated) transplants, depending on whether a biological relationship exists between the donor and recipient. Before receiving a kidney transplant, a person with ESRD must undergo a thorough medical evaluation to make sure that they are healthy enough to undergo transplant surgery. If they are deemed a good candidate, they can be placed on a waiting list to receive a kidney from a deceased donor. Once they are placed on the waiting 
Title: Kidney transplantation
Content:  Since medication to prevent rejection is so effective, donors do not need to be similar to their recipients. Most donated kidneys come from deceased donors; however, the utilisation of living donors in the United States is on the rise. In 2006, 47% of donated kidneys were from living donors. This varies by country: for example, only 3% of kidneys transplanted during 2006 in Spain came from living donors. In Spain all citizens are potential organ donors in the case of their death, unless they explicitly opt out during their lifetime.
Title: Transplantable organs and tissues
Content:  Kidney transplantation is the organ transplant of a kidney in a patient with end-stage renal disease. Kidney transplantation is typically classified as deceased-donor (formerly known as cadaveric) or living-donor transplantation depending on the source of the recipient organ. Living-donor renal transplants are further characterized as genetically related (living-related) or non-related (living-unrelated) transplants, depending on whether a biological relationship exists between the donor and recipient.
Title: Kidney disease
Content:  occur worldwide. The act of buying an organ through the black market is illegal in the United States. To be put on the waiting list for a kidney transplant, patients must first be referred by a physician, then they must choose and contact a donor hospital. Once they choose a donor hospital, patients must then receive an evaluation to make sure they are sustainable to receive a transplant. In order to be a match for a kidney transplant, patients must match blood type and human leukocyte antigen factors with their donors. They must also have no reactions to the antibodies from the donor's kidneys.
Title: Kidney transplantation
Content:  One of the earliest mentions about the possibility of a kidney transplant was by American medical researcher Simon Flexner, who declared in a reading of his paper on "Tendencies in Pathology" in the University of Chicago in 1907 that it would be possible in the then-future for diseased human organs substitution for healthy ones by surgery, including arteries, stomach, kidneys and heart. In 1933 surgeon Yuriy Vorony from Kherson in Ukraine attempted the first human kidney transplant, using a kidney removed six hours earlier from a deceased donor to be reimplanted into the thigh. He measured kidney function using a connection between the kidney and the 
Title: Organ replacement in animals
Content:  Kidney transplantation has so far only been performed with any degree of success on cats and dogs, most usually cats as they are particularly prone to kidney diseases. The School of Veterinary Medicine at U.C. Davis initiated the Renal Transplantation Program in 1987. Cats can tolerate transplantation from unrelated cats, but must be supported with immunosuppressive drugs for the rest of their lives. When the transplanted kidney is implanted in the recipient the original kidneys are usually left in place. There are currently ten centers in the world that offer kidney transplants for cats. Most are in the US. UC Davis have since abandoned their program. Kidney transplantation is a controversial treatment option, with longevity, quality of life, as well as ethical considerations. The United Kingdom permitted this procedure in 2003, but a review in 2013 suspended it. Many argue that it causes unnecessary suffering to donor animals.
Title: Kidney disease
Content:  Millions of people across the world suffer from kidney disease. Of those millions, several thousand will need dialysis or a kidney transplant at its end-stage. In the United States, as of 2008, 16,500 people needed a kidney transplant. Of those, 5,000 died while waiting for a transplant. Currently, there is a shortage of donors, and in 2007 there were only 64,606 kidney transplants in the world. This shortage of donors is causing countries to place monetary value on kidneys. Countries such as Iran and Singapore are eliminating their lists by paying their citizens to donate. Also, the black market accounts for 5-10 percent of transplants 
Title: Kidney transplantation
Content:  the donor's kidney, the textbook recommends using the right side because the right side has a wider choice of arteries and veins for reconstruction. Glen's Urological Surgery (2004) recommends putting the kidney in the contralateral side in all circumstances. No reason is explicitly put forth; however, one can assume the rationale is similar to that of Campbell, i.e. to ensure that the renal pelvis and ureter are most anterior in the event that future surgical correction becomes necessary. Smith's Urology (2004) states that either side of the recipient's pelvis is acceptable; however the right vessels are 'more horizontal' with respect to each other and therefore easier to use in the anastomoses. It is unclear what is meant by the words 'more horizontal'.
Title: Kidney transplantation
Content:  The transplant surgery takes about three hours. The donor kidney will be placed in the lower abdomen and its blood vessels connected to arteries and veins in the recipient's body. When this is complete, blood will be allowed to flow through the kidney again. The final step is connecting the ureter from the donor kidney to the bladder. In most cases, the kidney will soon start producing urine. Depending on its quality, the new kidney usually begins functioning immediately. Living donor kidneys normally require 3–5 days to reach normal functioning levels, while cadaveric donations stretch that interval to 7–15 days. Hospital stay is typically for 4–10 days. If complications arise, additional medications (diuretics) may be administered to help the kidney produce urine. Immunosuppressant drugs are used to suppress the immune system from 

Question: where do kidneys for kidney transplant come from?
Answer: living-donor.