Human fetal pancreatic islet tissue has several advantages as a transplant source for the amelioration of insulin deficiency in patients with Type I diabetes mellitus. It is now possible to obtain viable tissue, store and ship the tissue without adverse effects on the insulin secretory capacity, and transplant either minced tissue or isolated islet-like cell clusters following digestion and culture into animal models or man. A number of centers have undertaken studies of human fetal pancreatic allografts in man. Optimal results have occurred when pooled tissue from six to 20 donors has been implanted and a number of sites have been studied. The author's own experience in four recipients who did not receive immunosuppression has documented insulin secretion for up to 1 year in the absence of an anticytoplasmic islet cell antibody response on the part of the recipients. Nevertheless, the procedure has not resulted in insulin independence for the recipients and the implanted tissue has not secreted insulin in response to a glucose-amino acid challenge in a normal physiologic pattern. Thus, human fetal pancreatic transplantation for the treatment of Type I diabetes remains an experimental approach.