Hematopoietic cell transplantation (HCT) is an integral part of the treatment of acute myeloid leukemia (AML). Although AML is the most common indication for allogeneic HCT, the relatively small number of patients and the highly complex nature of the procedure often render prospective studies on HCT unfeasible. Observational studies using registry data serve as important sources of information under such circumstances. Thus, the Japanese Society of Hematopoietic Cell Transplantation (JSHCT) has been conducting a nationwide survey of HCT since 1993, and this registration program now covers >99% of transplantation centers in Japan. A constant increase in the number of HCT procedures has been noted with recent annual registrations recording more than >1,000 new AML patients undergoing allogeneic or autologous HCT. Since its establishment in 2010, the Adult AML Working Group within the JSHCT has been using this registry data to complete several studies focusing on various aspects of HCT in adults with AML, with particular attention paid to patient-, disease-, and transplantation-related factors. This article comprehensively reviews the results obtained from these studies and discusses the strengths and limitations of these kinds of registry-based studies.