Introduction: Paired kidney donation or exchange (PKD/PKE) has proven to be a boon for those with end stage renal disease (ESRD) whose potential living donors are unsuitable due to medical incompatibility. Initially started as a two-pair swap transplant, many kinds of donor-recipient chains have been introduced to help a large number of patients. Domino transplants involving altruistic donors have become commonplace and many countries now have national PKD programs. But the existence of ethical issues in the principle and execution of these PKD chains is a growing problem. The study aimed to examine these ethical conundrums.
Materials and Methods:  A PubMed search and review was performed of all articles pertaining to paired kidney donation and the ethical issues arising out of it. The various kinds of PKD and the donors and recipients involved therein were noted and analysed for the presence of ethical problems. The dialogues and expert comments arising in relation to these issues were studied extensively.
Results: There were approximately 200 articles which covered the development of PKD over the years. These studies were from a plethora of different nations and many discussed the formulation of PKD registries or databases – either separately or in conjunction with Deceased Donor Registries. Over time, PKDs have become increasingly complex due to the inclusion of altruistic or Non-Directed Anonymous Donors (NDADs). NDAD chains have become steadily longer; Non-simultaneous Extended Altruistic Donor (NEAD) chains have made PKD a balanced activity by bridging PKD and deceased donor registries. The availability of altruistic donors, however, is the limiting step in these chains. To widen the pool of altruistic donors, international donors were encouraged to join PKD programs in developed countries. But the financial divide between donors and recipients and the denial of long-term medical benefits to such altruistic donors has led to numerous questions by ethical experts. Long dialogues into the potential exploitation of Filipino NDAD donors has led to a rule-of-thumb by experts – donor-recipient pairs which are monetarily divided should not be considered compatible.
Discussion: PKD is an innovative measure that has great potential in providing respite to patients with ESRD who can be benefitted from living donation; on the other hand, international collaboration has given way to greater exploitation of the poor and vulnerable and caused possible breaches of the Declaration of Istanbul. We need to be more responsible in executing such novel concepts in the future.
Conclusion: Organ transplantation will keep witnessing new ideas to help narrow the gap between the demand and supply of organs for therapeutic purposes. It is our fundamental responsibility to weigh the benefits of these ideas against their possible ethical loopholes and to ensure their execution in an ethically transparent manner.