Although solid organ transplantation (SOT) is considered one of the exceptional medical victories of the 20th century, there is a widening gap between available organs and potential recipients. In the United States, every 9 minutes, another person is added to the transplant waitlist, and on average, 17 people die per day while waiting to receive SOT (Health Resources and Services Administration, 2021). As a result, transplant teams are often considered custodians of this limited and valued resource for patients with advanced or end-stage organ disease (ESOD). This chapter focuses on areas most applicable to the presurgical psychosocial assessment of adult SOT candidates (PPA-TC), incorporating a brief review of the distinct domains across the four most common organ transplants and associated disease states. Pretransplant psychosocial, behavioral, and cognitive factors that have been empirically linked to posttransplant outcomes are reviewed to help guide why and how to best assess adult patients being considered for liver, heart, lung, or kidney transplantation (LT, HT, LGT, KT, respectively). Guidelines for evaluating