Islet autoimmunity precedes the onset of type 1 diabetes. It has generally been assumed that beta cell loss occurs during the period of time prior to hyperglycemia and diabetes onset. We examined the pancreata from 18 individuals with one or more islet autoantibodies but no clinical diagnosis of diabetes obtained from the network for Pancreatic Organ Donors with Diabetes. Histology sections were compared to 24 healthy control donors and donors with diagnosed type 1 diabetes. Pseudo-atrophic islets were present to a greater degree in type 1 diabetes compared to islet autoantibody donors. Insulitis was sparse but the amount was similar between type 1 diabetes and islet autoantibody donors. Controls did not have any evidence of islet destruction. Beta cell mass was quantified in the pancreas sections from all three groups, and interestingly beta cell mass was greater in the islet autoantibody positive donors compared to controls (p = 0.02). Despite this, rate of ki-67 was not significantly different in controls and islet autoantibody positive. These findings are of central importance to understanding the beta cell biology and timing of loss during the pre-diabetic period.