Whereas there is general agreement about the biochemical diagnosis of hyperinsulinism, the value of imaging to differentiate diffuse from focal pancreatic lesions is still a matter of debate. We describe a case of multiple adenomas of the pancreas in an eleven year-old boy. The source of hyperinsulinism was detected by pancreatic ultrasound examination and confirmed by MRI as a single adenoma of the pancreas. These radiological exams did not identify three other pancreatic adenomata. Our report outlines the difficulties in anatomically localizing the source of excessive insulin secretion in cases of hyperinsulinemic hypoglycemia.