Organ Acquisition Cost Centers (OACC) were designed to encourage and incentivize hospitals to provide transplantation services. The purpose of this article (Part I) is to familiarize transplant professionals and transplant center administrators with the regulations that govern OACC. An historical perspective of the evolution of these regulations is necessary to better understand the basic principles underlying this complex area of transplant finance. There is a wide variation in transplant center OACC reporting, suggesting under-reporting by some and overreporting by others. Correct reporting is essential since OACC are auditable. We have surveyed 13 audits by the Office of the Inspector General (OIG) of transplant center OACC in an attempt to identify trends in reporting practices by transplant centers that are not deemed acceptable by the OIG. We discuss these findings in the context of some basic definitions that refer specifically to cost accounting principles necessary for accurate reporting of OACC.