Childhood obesity has become a pandemic health care problem. A complication of childhood obesity is type 2 diabetes mellitus which has increased 10-fold in the past 20 years. A serious complication of type 2 diabetes mellitus is hyperglycemic hyperosmolar syndrome (HHS). The following case is an obese adolescent boy with a newly diagnosed HHS. The demographic and clinical characteristics of our case and those of 17 other cases from recently published small case series are presented. Of the 18 cases, there were 13 deaths (72%). The purpose of this report and literature review is to emphasize the importance of early diagnoses and treatment of pediatric HHS.