Background: Upon evaluation of patients with recurrent hypoglycemia, both exogenous and endogenous causes should be excluded. Among endogenous hyperinsulinemic hypoglycemia (EHH) pathologies, Insulin Autoimmune Syndrome (IAS), even though extremely rare, must be considered. Most cases of IAS have been reported in the Oriental population, mostly Japanese. No gold standard of care for this condition has been established. Clinical Case: This is the case of an 82 year-old obese female patient with dyslipidemia, obstructive sleep apnea, and osteoarthritis that comes to the Endocrinology clinics for evaluation due to recurrent episodes of hypoglycemia. She refers that for the last three years she had been presenting with multiple episodes of symptomatic hypoglycemia, even levels as low as 30 mg/dL, requiring multiple hospitalizations. Consequently, she refers a 15-pound weight gain because of multiple daily snacks. Home medications were simvastatin and diclofenac. She denies using insulin, sulfonylureas, other hypoglycemic agents, alcohol, or illicit substances. Abdominal MRI and PET CT scan were remarkable only for an atrophic pancreas without focal masses. Patient was hospitalized for a supervised 72-hour fast, resulting in severe hypoglycemia within 14 hours with elevated insulin levels at 46.3 uIU/mL (1.7-31.0 uIU/mL), elevated C-peptide levels at 5.79 ng/mL (0.9-4.3 ng/mL) and elevated insulin antibodies 53µU/mL (<5µU/mL). Patient showed sufficient hepatic reserve after glucagon administration as well as intact cortisol and growth hormone axis upon severe hypoglycemia. With these results, a diagnosis of IAS was made; not associated with other autoimmune diseases, or with medications with sulfhydryl groups, such as the cases already reported on literature. This condition represents a therapeutic challenge because there is no gold standard of care. Literature recognizes diverse treatment options that range from diet modification to more aggressive therapies, including plasmapheresis and immunosupressants. Our patient was managed with diet modification including frequent snacks and Diazoxide with the goal of decreasing insulin levels and inducing hyperglycemia. Diazoxide therapy achieved a steady euglycemic state and decreased insulin antibodies. Patient developed intolerable bilateral lower extremity edema and treatment was modified to complex carbohydrates, frequent snacks in the daytime and Diazoxide only at bedtime, which is the longer fasting period. Patient has remained without episodes of hypoglycemia and diabetes has not been diagnosed since starting treatment two years ago. Conclusion: Early recognition of IAS is essential in order to avoid unnecessary studies and procedures which could delay management. Although no gold standard therapy has been identified for this condition, our case report identifies Diazoxide as a compelling medical treatment.