The question of organ donation is highly debated amongst Rabbanim and religious circles. Its question touches upon several Halachic prohibitions, which vary based on the state of the patient whose organ is being used. We have divided the ruling to four distinct cases: 1) If the person is alive and healthy: In such a case, the question is raised whether according to Halacha one may donate an organ and take a chance of putting his own life at risk. 2) If the patient is alive and unhealthy: In such a case, donating the organ could be tantamount to murder. 3) If the person is dead: In such a case, donating the organ touches upon the prohibition of benefiting from the dead, and not burying the dead. 4) If the patient is brain-dead: The question in such a case is whether he is still viewed as living. Practically, in the medical field, organ transplants are usually only performed to healthy individuals, or to people who are brain-dead [cases 1 and 4] and not to living people who are unhealthy [case 2] or to people who have already died [case 3]. The following is a general background on the subject and the opinions amongst the Poskim who discuss it. Obviously, no individual is to make a decision in such serious matters, and sign on an organ donor card, without first discussing it with a Rav who is an expert in this field.
Case 1: Organ donation from one who is alive and healthy: It is permitted for one who is healthy to donate a non-vital organ from his body for the sake of saving the life of another Jew. This includes the following transplants: kidney, bone, bone marrow; whole blood donation; Platelet blood donation; Stem cell donation. Some Poskim however question the allowance of donating an organ, such as a kidney, that may enter the person into danger in a case that it is not certain that the organ receiver will definitely be saved.
Case 2: Organ donation from a Goses or one who is alive and unhealthy: It is forbidden, from both a medical and Halachic perspective, to perform organ transplants from unhealthy individuals whose health can deteriorate as a result of the loss of the limb. Likewise, it is absolutely forbidden for an organ donation to take place prior to death, when the person is in a state of Gesisa and is still Halachically considered alive. [In the first years that heart transplants were practiced, the Gedolei Haposkim unanimously agreed that doing so was absolutely forbidden and considered murder, as often the hearts were removed while the person was still Halachically deemed to be alive, hence murdering the patient, and likewise, in most cases the patient who received the new heart would die.]
Case 3: Organ donation after the death of the patient: In general, it is forbidden to remove organs from the deceased and store it in an organ bank for eventual use in a living person, just as one may not perform an autopsy for purposes of medical science, as explained in the previous Halacha. Nevertheless, regarding certain parts of the body, there are Poskim who are lenient to permit organ transplants even if the matter is not life threatening. If another Jew is currently in need of an organ transplant to save his life, some Poskim rule it is permitted to use the limb of a deceased to perform the transplant on this Jew. Other Poskim, however, prohibit organ donation from a deceased even to help save the life of a Jew with a life-threatening condition.
Case 4: Brain dead patient: Whether one may remove an organ from a person who is 100% brain dead is dependent on the dispute amongst the Poskim in whether one who is 100% brain dead is considered dead or not, as explained in E. According to the lenient opinion there, it would be permitted to perform organ transplants from 100% brain-dead patients. However, according to the stringent opinion there, it would be absolutely forbidden to do so, and one who does so is considered a murderer. According to all, it is absolutely forbidden to perform organ transplants from patients who are in a coma or vegetative state, and are not brain dead. Practically, the Poskim conclude that it is forbidden to perform an organ transplant from a Jewish brain-dead patient, and thus in Eretz Yisrael, it is forbidden for one to sign up for such transplants. However, it is permitted for a Jew to receive an organ transplant in the Diaspora, where the limb is taken from a gentile.
Signing on an organ donor card: Based on all the above information, even if one were to hold like the lenient opinion in Case 3 [that allows organ donation from a dead body in order to save a life], one may not sign an after-death organ donation consent form [such as on the driver’s license], unless provisions are made for it to comply with Halacha, per the directive of a Rav who is knowledgeable in these matters. Halachic matters that must be considered upon signing such a form are: 1) Perhaps we rule like the stringent Poskim above that every organ must be buried and cannot be donated in any situation. 2) Perhaps the organ will go to an organ bank or hospital and not directly to a Jew in need. 3) Perhaps the organ will not go to a Jew at all; 4) Perhaps the organ will be removed after clinical death, but prior to Halachic death, which is tantamount to murder. Most organ donations take place from a brain-dead patient which is under dispute if he is considered Halachically dead. One is to contact his Rav for direction in all of these matters. See http://www.hods.org/ for a USA based Halachic organ donor card which has options of choosing the Halachic opinion one follows, and/or the requirement for consultation with one’s Rabbi after death. See https://www.adi.gov.il for an Israeli based donor card, with a Halachic option. One is to discuss the matter with his Rav prior to all decisions.]
 See Nishmas Avraham 2:339 pp. 294-299 [regarding Goses]; pp. 451-482 [regarding brain-dead]; p. 526 [regarding deceased]; Journal of the RCA [110 pages long] titled “Halachic Issues in the Determination of Death and in Organ Transplantation”; Article of Rav Melameid on http:::www.yeshiva.org.il:midrash:460#8b;
 See here: https://www.government.nl/topics/organ-tissue-donation/question-and-answer/if-i-am-a-registered-donor-what-will-happen-to-my-body-after-my- death#:~:text=Organs%20that%20can%20be%20transplanted,are%20transplantable%20forms%20of%20tissue.
 See Igros Moshe Y.D. 2:174-4; Tzitz Eliezer 10:25-7; Yechaveh Daas 3:84; Nishmas Avraham 2:530-535
The Halachic issues involved with organ donations when alive: Damaging one’s body, and entering oneself into possible danger. The following Poskim rule one is not obligated to risk his life on behalf of saving another Jew: Admur 329:8; 2nd opinion in parentheses in Admur Choshen Mishpat Hilchos Nizkeiy Haguf Vehanefesh Halacha 7; Issur Viheter 59:38; Elya Zuta 329:4; Smeh 426:2 based on omission of all Rishonim and Poskim; M”B 329:19; The following Poskim rule one is obligated to risk his life to help save a Jew whose life is definitely in danger. [1st opinion in Admur Choshen Mishpat Hilchos Nizkeiy Haguf Vehanefesh Halacha 7; Hagahos Maimanos Rotzeiach 1:14 in name of Yerushalmi; Radbaz Leshonos Harambam 1582]
 Igros Moshe ibid; Tzitz Eliezer ibid; Poskim ibid
 Igros Moshe 1:103
 Nishmas Avraham p. 533 in name of Gedolei Haposkim
 Nishmas Avraham p. 533
 Minchas Yitzchak 6:103
 See Nishmas Avraham p. 294
 Tzitz Eliezer 10:25; Igros Moshe C.M. 2:72; Minchas Yitzchak 5:7; See Admur 330:7 that we no longer remove the baby from a pregnant woman who passes away before childbirth, as we suspect that she is still alive and cutting open her stomach to remove the child will kill her. and by the time we can determine her death, the fetus has certainly died
 See Minchas Yitzchak 5:7-8; Igros Moshe C.M. 2:72; Tzitz Eliezer 10:25; See Nishmas Avraham 480 for opinion of Rav SZ”A regarding the Diaspora which is mainly gentiles
 See Nishmas Avraham 2:339 p. 526
The Halachic issues involved with organ donations from the dead: a) Desecration of the body. 2) Prohibition against benefiting from the body. 3) Transgressing the Biblical command to bury the body. [See previous Halacha regarding amputation]
 Such as corneal donation; Skin grafting
 See Har Tzevi Y.D. 276; Shevet Miyehuda p. 314 of Rav Unterman [says the limb is considered alive when transplanted]; Seridei Eish 2:120; Yabia Omer Y.D 3:22-23; Other Poskim however prohibit this: See Minchas Yitzchak 5:8; Tzitz Eliezer 13:91; Shevet Halevi 1:211; Rav SZ”A in Nishmas Avraham ibid; See Darkei Chesed 10:5 that all Gedolei Yisrael have protested the removal of the eye for the sake of a corneal transplant to help save the eyesight of an individual “as there is no greater desecration of the dead than this” and it is forbidden to benefit from the dead.
 Rav SZ”A in Minchas Shlomo Tinyana 86:5
 Minchas Yitzchak 5:7-22, based on Radbaz 3:627; Tzitz Eliezer 13:91
 The reason: As the Torah required the entire body to be buried, and there is no Mitzvah to help save another’s life through donating one’s organs. [Poskim ibid]
 See the journal of the RCA [110 pages long] on this issue titled “Halachic Issues in the Determination of Death and in Organ Transplantation”
 See Nishmas Avraham 2:339 pp. 451-482 in great length for opinions, and correspondence letters of Gedolei Haposkim; Tzitz Eliezer 10:25; Minchas Yitzchak 5:7; Rav Elyashiv; Rav SZ”A as detailed in Nishmas Avraham ibid and the above journal
 See Nishmas Avraham ibid p. 480
 See Nishmas Avraham ibid p. 477 and 479 in name of Rav SZ”A and Minchas Yitzchak; Heard from Rav Yaakov Yosef za”l