The health-related quality of life (HRQL; Health Utilities Index Mark 2) and the fear of hypoglycemia (Hypoglycemia Fear Survey) were assessed after islet transplant; the impact of a single islet infusion and of the metabolic outcome were determined. A control group included 166 patients with type 1 diabetes. Islet transplant had no impact on overall HRQL. Prior to transplant, islet recipients had more fear of hypoglycemia than controls (P<0.000001), but this improved up to 36 months after transplant (P<0.00001, pretransplant vs. each time point). With a single islet infusion, this fear improved substantially (P<0.00001), but improved further with subsequent islet infusions (P</=0.01). Fear of hypoglycemia correlated with the occurrence of hypoglycemia (r=0.47, P=0.01), and even more so with blood glucose stability (r=0.56, P=0.0007) and insulin requirement (r=0.69, P=0.000002).