The story of a middle-aged male with Graves’ toxicosis who started to have recurrent hypoglycemic episodes following the introduction of antithyroid drugs is beautifully described in this case scenario. There is an elaborate discussion on the rational approach to spontaneous hypoglycemia, and in our patient, thorough investigations including a formal supervised fast test established endogenous hyperinsulinism as the probable etiology. A negative pancreatic scan coupled with positive anti-insulin antibody in plasma clinched the ultimate diagnosis of Hirata’s syndrome; the self-limiting nature of the disease further supported our conclusion.