Children and adolescents with type-I-diabetes are examined with regard to the influence of Intensified Conventional Insulin Therapy (ICT) on metabolic control, insulin requirement and weight development. On average the period of treatment with ICT lasted 10 months (SD: 3 months). The average insulin requirement under ICT slightly increased from 0.82 to 0.87 I.U./kg BW. The need for longer acting insulin decreased from 0.5 to 0.35 I.U./kg BW. Snacks were not necessary. On average the insulin-BE quotient increased to 2.4 I.U./BE in the morning, 1.9.I.U./BE at lunch time and 2.1 I.U./BE at night. Compared to a group being treated with Conventional Insulin Therapy the quality of metabolic control improved. Within the ICT group the part of well controlled patients rose from 10 to 30% whereas the part of poorly controlled patients decreased from 30 to 10%. Provided that Continuous subcutaneous insulin infusion pumps (CSII) cannot be applied, ICT represents the best form of therapy for well educated and highly motivated diabetics aged 12 years old or more.