All eligible patients will be assigned to receive insulin Detemir once daily before breakfast. Short acting insulin analog, Novorapid, will be used for mealtime insulin. The starting dose of insulin Detemir will be individually determined.Based on self-measured fasting blood glucose levels, insulin doses will be titrated throughout the trial, aiming at pre-breakfast and premeal concentrations of 90-180 mg/dl for subjects aged 6-12 years and 80-130 mg/dl for subjects aged 13-18 years.Patients that after 4 weeks titration phase will not achieve the target blood glucose and up titration of insulin Detemir cannot be done, due to hypoglycemic episodes would be switched to treatment consist of twice daily insulin Detemir. If the target blood glucose are not achieved at the end of the 4 weeks titration phase, but further up titration is possible and patient does not suffer from hypoglycemic episodes, the titration period would be extended and patient would not be switched to treatment with 2 injections of insulin Detemir.When achieving blood glucose targets patient will continue until study end on the maintenance phase.