A kidney transplant is a surgical procedure performed to treat kidney failure. The kidneys filter waste products from the blood and remove them from the body through the urine. It also helps maintain fluid and electrolyte balance. When the kidneys fail, the body builds up waste products, which can be very bad. Some people who have kidney failure are eligible for a kidney transplant. In this procedure, one or both kidneys are replaced with kidneys from a living or deceased donor.