Of 89 pancreas transplants performed at the University of Minnesota between July 1978, and March 1983, 36 have been segmental grafts from living-related donors (17 HLA-identical siblings, 6 identical twins, 13 HLA-mismatched relatives). All recipients had been diabetic for at least 10 years and all donors were at least 10 years older than the ages of onset of diabetes in the recipients; in the case of sibling donors, no other siblings or family members other than the recipient were diabetic. Changes in plasma glucose and serum insulin levels occurred in most donors postoperatively, but glucose tolerance tests usually remained normal. Of the 36 grafts from related donors, 16 are currently functioning (12 were technical failures), as compared with 10 of 53 from cadaver donors (10 were technical failures). The pancreatic ducts were left open, injected with synthetic polymers, or anastomosed to a Roux-en-Y limb of recipient jejunum. All techniques have been associated with successes and failures, but we currently prefer the enteric-drainage technique. The patient survival rates for recipients of transplants from related versus cadaver donors were 94% versus 78% (P less than .013); the respective graft survival rates were 43% versus 20% (P = .25). When only technically successful grafts were considered, the one-year function rates were 65% for pancreas grafts from related donors (n = 29) versus 25% for those from cadaver donors (n = 43) (P = .005). The highest success rate has been in azathioprine-treated recipients of technically successful pancreas transplants from related donors of a previous kidney (3 of 3 grafts from HLA-identical siblings and 3 of 3 from HLA-mismatched relatives are functioning). However, 7 of 9 technically successful grafts from HLA-identical siblings in nonuremic, non-kidney-transplant recipients treated with cyclosporine are also functioning (one-year graft survival rate of 76%). The results in nonuremic, non-kidney-transplant recipients of mismatched related grafts have not been so good, and only one of 5 technically successful grafts in this category is currently functioning. However, this patient has been treated with cyclosporine, azathioprine, and prednisone (triple therapy)--an immunosuppressive regimen we have recently applied with success in nonuremic, non-kidney-transplant recipients of cadaveric grafts.(ABSTRACT TRUNCATED AT 400 WORDS)