Autologous human islet transplantation to mitigate or prevent surgically induced diabetes after total pancreatectomy for the relief of chronic pancreatitisinduced pain was pioneered in the late 1970s. Islet allotransplantation using islets from human donors to treat type 1 diabetes was first reported several years later. Over the last 40 years, methods for clinical islet transplantation have been methodically standardized to become the methods used today. Human islets are also isolated from donors with pathologies with the aim to conduct a broad range of investigational studies. Human islet isolation undertaken for research can provide the opportunity to further optimize and develop methods that may be helpful in the clinic. The variability of conditions associated with donor and pancreas makes consistent success in isolating islets a challenge, thus, we should re-evaluate the effectiveness of our methods of islet isolation. In order to do this, we must first consider that the intended outcomes for clinical islet transplantation and experimental investigations involving islet isolation are, in fact, quite different and that these differences impact the status and future considerations of islet isolation procedures.