Insulinomas are the most common cause of hypoglycemia, resulting from endogenous hyperinsulinism. The diagnosis of insulinoma is established by demonstrating inappropriately high serum insulin concentrations during a spontaneous or induced episode of hypoglycemia. Most insulinomas are islet-cell tumors. They are often small (<2 cm), benign, and difficult to localize with current imaging techniques. Insulinomas can be detected using either noninvasive procedures (e.g., transabdominal ultrasonography, spiral CT, MRI, ¹¹¹In-pentetreotide imaging, and ¹⁸F-l-dihydroxyphenylalanine PET) or invasive procedures (e.g., endoscopic ultrasonography) or a selective arterial calcium stimulation test with hepatic venous sampling. We performed ⁶⁸Ga-DOTATATE PET/CT on 3 patients with insulinoma. All patients' insulinomas were shown clearly with ⁶⁸Ga-DOTATATE PET/CT. ⁶⁸Ga-DOTATATE PET/CT imaging may be a useful noninvasive imaging technique to localize insulinomas preoperatively.