β‐cell replacement therapy via islet transplantation has had renewed interest, due to the recent improved success. In order to make such a therapy available to more than a few of the thousands of patients with diabetes, new sources of insulin‐producing cells must be readily available. The recent conceptual revolution of the presence of adult pluripotent stem cells in bone marrow and in most, if not all, organs suggests that adult stem cells may be a potential source of insulin‐producing cells. Pancreatic stem/progenitor cells or markers for these cells have been sought in both islets and ducts. There is considerable evidence that such cells exist and several candidate cells have been reported. However, no clearly identifiable adult pancreatic stem cell has been found as yet. The putative pancreatic stem cells will be the focus of this review. Copyright © 2002 John Wiley & Sons, Ltd.