Many Jews mistakenly believe that halacha (Jewish law) forbids organ donation.
Saving a Life – Pikuach Nefesh
Rabbinic authorities agree that the mitzvah of saving a life prevails over all prohibitions. (With the exception of three: idolatry, incest and shedding blood). As our sages said:
“Whoever saves a single life is considered by Scripture to have saved the whole world”
Prohibitions
There are three prohibitions most often cited as forbidding organ donation.
Mutilation of the Dead – Nivul Hamet
The Torah forbids needless mutilation of the dead. That’s why autopsies are not generally performed. But according to many authorities, Jewish law does permit autopsies when the results have a real and immediate chance to save lives.
And in the case of organ donation, which definitely saves lives, Pikuach Nefesh prevails and most rabbis agree that it is permitted.
Delaying Burial – Nalanat Hamet
Torah prohibits the postponement of burial. However, families often choose to delay burial to allow relatives and friends time to travel from distant locations. And although organ removal may delay burial by a few hours, most rabbis agree that it is permitted in order to save a life.
Benefiting from a Body – Hana’at Hamet
There is a prohibition against benefiting from the dead, for example, selling a body for medical research. But in the case of organ donation, which saves lives, Pikuach Nefesh prevails and most rabbis agree that it is permitted.
Saving a Life Overrides these Prohibitions
In all of these cases, the prohibitions must be weighed against the positive commandment to save a life.
The prohibitions are in place because it is important to treat the dead with great respect and dignity, since they once hosted life.
But rabbis agree that by allowing someone, upon their death, to save one or more lives, you ARE affording utmost respect and dignity to the human body
Of course, organ donation must be carried out according halachic laws. And this is where some disagreements arise. (See Remaining Controversies)