In this article, the author discusses the prevalence of insulin autoantibodies (IAA) and endogenous insulin secretion in Saudi patients at the onset of diabetes. A positive result, defined as a value greater than 3 SD above the mean binding of normal, was found in 8 (7.6%) of 105 of the patients with diabetes and in 3 (5.7%) of 53 of the healthy control subjects. The relation between the presence of IAA and the pancreatic beta cell secretory activity was studied by determining the levels of insulin and C-peptide in the fasting state and 6 minutes after intravenous injection of 1 mg glucagon. All the IAA positive subjects had a response to glucagon stimulation test. A positive correlation was found between basal and after stimulation for both insulin and C-peptide (r = 0.79, P < 0.001; r = 0.85, P < 0.001 for insulin and r = 0.76, P < 0.001; r = 0.81, P < 0.001 for C-peptide, respectively). Therefore, the current finding indicates that there is no direct effect of IAA on the pancreatic beta cell potential activity in Saudi patients with diabetes at the time of diagnosis, suggesting further that these patients have no insulin deficiency or have mild insulin dependency.