Severe hypoglycemia after Roux-en-Y gastric bypass surgery (RYGB) is an increasingly recognized condition, characterized by neuroglycopenia and inappropriately elevated insulin concentrations that occur primarily in the postprandial state. Both pathophysiology and treatment of this disorder remain elusive, but it has been postulated that hyperplasia and/or hypertrophy of beta-cells due to morbid obesity and/or postsurgical nesidioblastosis may contribute.