Pancreatic islet transplantation has emerged as an effective treatment for type 1 diabetes with severe hypoglycemic unawareness. A major benefit of islet transplantation is that it does not require major surgery. Islet transplants, though significantly improving, are still mostly done on an experimental basis. In Japan, phase II clinical trial to confirm the safety and efficacy of islet transplantation has been in progress. The induction of the regenerative medicine approach is also expected to accelerate the growth of islet transplantation. In this review, we give an outline about a summary of islet transplantation in Japan and the future prospects based on the latest findings.