Insulinoma is a rare neuroendocrine tumor with an incidence of 4 per 1 million persons per year, which may occur as a unifocal sporadic event in patients without an inherited syndrome or as a part of multiple endocrine neoplasia type 1. Key neuroglycopenic and hypoglycemic symptoms in conjunction with biochemical proof establish the diagnosis. Once the diagnosis is established, the insulinoma is preoperatively localized within the pancreas with the goal of surgical excision for cure. This review discusses the historical background, diagnosis, and management of sporadic insulinoma.