A case of insulinoma who had episoic bizarre behaviour is presented here. Pre-operative fasting and two hour post-prandial blood sugar values indicated hypoglycemia with inappropriately high insulin levels. USG and CT scan of the abdomen revealed a tumor of head of the pancreas. The tumour was enucleated surgically. Histopathological examination confirmed the origin as islet cells. The post-operative blood sugar and insulin levels were found to be in normal range. Since insulinoma is a rare pancreatic tumor, differential diagnoses along with a brief review of the literature is also presented.