Global prevalence of type 2 diabetes mellitus in children is rising recently, likely due to an increasing rate of childhood obesity. In Taiwan, an annual program of mass screen for diabetes with two-staged design, i.e. diagnosis by fasting plasma glucose when glycosuria was positive in two consecutive urine samples, has been conducted since 1992 for all schoolchildren aged 6 to 18. A recent survey showed that the incidence of type 2 diabetes is 6-fold higher than those of type 1 diabetes. The prevalence of diabetes is elevated during puberty and is higher in girls than in boys. Obesity is the most important risk factor of type 2 diabetes in childhood and adolescence. Besides, genetics, family history, polycystic ovarian syndrome, ethnicity, and puberty are also risk factors of pediatric diabetes. We also briefly discuss the current state of management of obesity and type 2 diabetes, with special emphasis on behavioral and lifestyle modification, the need to create adequate and safe environment, and the psychological as well as family support in children and adolescents. Limited experience of the pharmacological agents in terms of their long-term effect and safety is also discussed.