For more than 20 years, the Organ Procurement and Transplantation Network (OPTN) has developed policies and bylaws relating to equitable allocation of deceased donor organs for transplantation. United Network for Organ Sharing (UNOS) operates the OPTN under contract with the Health Resources and Services Administration (HRSA) of the U.S. Department of Health and Human Services (HHS). Until recent years, the OPTN had little defined authority regarding living donor organ for transplantation except for the collection of data relating to living donor transplants. Beginning with the implementation of the OPTN Final Rule in 2000, and continuing with more recent announcements, the OPTN's role in living donation has grown. Its responsibilities now include monitoring of living donor outcomes, promoting equity in nondirected living donor transplantation and ensuring that transplant programs have expertise and established protocols to promote the safety of living donors and recipients. The purpose of this article is to describe the evolving mandates for the OPTN in living donation, as well as the network's recent activities and ongoing efforts.