Six recipients have received organs from six donors in simultaneous operations at the Johns Hopkins Hospital in Maryland, US.
The procedure was made possible after an altruistic donor - neither a friend nor relative of any of the six patients - was found to match one of them.
Five patients had a willing donor whose kidney was incompatible with theirs, but it did match another in the group.
This meant that suddenly, there were six people who could receive an organ.
The operations were carried out simultaneously to make sure no-one backed out after their loved one had received a kidney.
"All 12 are doing great, the six kidneys are working well," said Dr Robert Montgomery, director of the transplant centre at the Johns Hopkins hospital.
The hospital has been one of the pioneers of this system which matches up several groups of people at one time, BBC reports.
It aims to circumvent the problem of altruistic donors ending up in arbitrary allocation systems where only a single patient’s needs are served.
The hospital has been carrying out these simultaneous transplants for three years: in 2005, the first triple procedure was performed, a year later, the first five-way.
Nearly 100 medical professionals were needed to make the complex series of transplants possible, from immunogeneticists to hinder rejection to psychologists.
If all goes to plan, each patient can expect their new kidney to last for as long as 20 years.