A large number of children with type 2 diabetes mellitus (T2DM) and a small number with a slowly progressive form of type 1 diabetes mellitus (SPT1DM) have been detected by a urine glucose screening program conducted at Japanese schools since 1974. The incidence of T2DM in children has increased over the last 3 decades and is estimated to be approximately 3.0/100,000/year, which is twice as that of T1DM. In contrast, SPT1DM in children is more prevalent in Asians, particularly Japanese, and exhibits unique clinical features that differ from those of the rapid onset form of T1DM, usually seen in Caucasians. In the first part of this review, we summarize the urine glucose screening program conducted at Japanese schools and clinical characteristics of the 2 diabetic subtypes in Japanese children. In recent years, concerns regarding childhood diabetes in Asian countries, including Japan, have risen, and medical care for the same is exceedingly developing. Intensive insulin therapy such as basal-bolus therapy by multiple daily insulin injections and pump therapy, both using insulin analogs, has been increasing in pediatric patients with T1DM. In addition, various antidiabetic medications have been introduced for children with T2DM. In the second part of this review, we describe treatment of Japanese children with T1DM and T2DM and changes in glycemic control as a result of development of the treatment.