Expert-opinion elicitation (EOE) is a heuristic process for gathering evidence and data or answering questions on issues/problems of concern. The Delphi method (DM) is the most frequent technique used to obtain structured elicitation of expert opinions. It has been increasingly applied in medicine to produce guidelines and to evaluate the appropriateness of diagnostic procedures. In this study, a DM has been used as structured EOE process to assess the appropriateness and clinical priority of a data set-based informative system in the context of the Liguria-Trento Transplant Network (LTTN) Project, funded by Italian Ministry of Health. The original data set was obtained by using an interdisciplinary pool of regional experts (n = 60). This data set held 1506 items stratified in 21 categories at various surgical phases (preoperative, intraoperative, and postoperative) and transplantation types (liver, kidney, and kidney/pancreas) in adult and pediatric recipients. Some categories included cadaveric donor management, organ allocation, and acute liver failure. In the second DM round, the data set was subjected to a panel of extraregional, independent experts (n = 9) to assess scores ranging from 1 to 9 on each item, based on increasing appropriateness/priority, according to RAND/UCLA Appropriateness Method. The overall agreement between experts was 95.88%, whereas disagreement and uncertainty were 0.13% and 3.98%, respectively. A major uncertainty occurred for the data set concerning the multiorgan cadaveric donor, for liver transplantation, and for kidney transplantation in adult recipients. The use of a structured EOE process may represent an effective strategy to define the appropriateness and prioritization criteria of a large data set in the field of solid organ transplantation.