Pancreas and islet transplant recipients are monitored using various metabolic and imaging methods. The inaccessibility of the transplanted whole pancreas and of the isolated islets poses specific problems (eg, all assessment techniques are indirect). Although successful pancreas transplantation typically restores normal glucose homeostasis, islet transplantation into the liver does not completely normalize islet hormone secretion and glucose metabolism. Development of better testing strategies, such as direct islet imaging, will significantly advance the field.