During the period from 1974 through 1988, we annually examined approximately 225,000 to 386,400 school children residing in Tokyo for glycosuria to detect juvenile diabetes. If the first test was positive for glucose, glycosuria was confirmed by a second test. In children who gave a positive result in both the first and second tests 0-GTT were performed. All 124 patients were diagnosed as NIDDM according to the criteria of the WHO Report on Diabetes of 1985. The incidence of NIDDM in children in Japan has increased in recent years and from 1984 to 1986 was approximately 3.8 per 100,000 per year. The frequency of NIDDM increases with age up to 14 years. In about 84% of cases, the body weight at diagnosis is more than 20% above the ideal weight and the height is often above average. There is a high frequency in families with a history of diabetes. Diet and exercise therapy in newly diagnosed patients irrespective of the presence or absence of obesity may result in remission, but some cases may require insulin therapy or oral administration of a hypoglycemic drug to obtain a better glycemic control. Children with NIDDM are more likely to be complicated by incipient retinopathy within two years after diagnosis than those with IDDM. Therefore, it is important to keep strict glycemic control to prevent diabetic complications in NIDDM children just as in juvenile onset IDDM.