Fifteen cases of insulinoma were managed at HUKM over a period of 20 years. Although all patients presented with neurological symptoms, the diagnosis was delayed in all. Fasting hypoglycaemia and the measurement of C-peptide levels eventually made the diagnosis. Pre-operative localization investigations were not particularly useful. Intraoperative ultrasound (IOUS) detected 72% of the insulinomas, while 93% of the insulinomas were identified intraoperatively by palpation. All the insulinomas were detected intraoperatively with the combination of the two techniques. Twelve of 15 patients had benign adenomas including one patient with MEN-1 syndrome. Two patients had malignant insulinomas. One patient refused surgery. Nine patients underwent pancreatic resections and the remaining 5 patients had the adenomas enucleated.