The missing insulin production of the pancreas is replaced by individual administration of different insulin preparations into the subcutaneous fat through injections or an insulin pump.In a patient with insulin deficiency, the administration of basal insulin must not be discontinued in any circumstances even if it may be necessary to reduce the dose in certain situations.A regime based on multiple daily insulin injections is the primary treatment mode in a patient with type 1 diabetes. It mimics normal insulin secretion at night and between mealtimes (basal insulin) as well as during mealtimes (mealtime insulin).Even in good diabetes control the blood glucose concentrations vary (due to, e.g., variation in insulin absorption, food composition and gastric emptying as well as stress, sickness, exercise, menstrual cycle). Temporary high concentrations are corrected with additional doses of rapid-acting insulin (corrective insulin) administered at meals.The patient is taught to adjust the insulin dosage him-/herself according to the daily rhythms, eating patterns, exercise and self-monitoring of blood glucose (plasma glucose concentration). Good treatment results are based on sufficient guidance as well as continuity of carethe patient's acceptance of the disease as a part of one's own lifesufficient and reasonable self-monitoring of blood glucose and actions taken according to the measurement results the ability of the patient to master the daily care of his illness shared, neutral and empowering problem solving. The individual aims and modes of treatment should be decided with the patient, taking into account the current life situation, the patient's proneness to hypoglycaemia and the ability of the patient to carry out the treatment himself/herself.Hypoglycaemias and the fear of them may pose an essential obstacle to good control of diabetes. If good glycaemic control is not achieved (HbA1c exceeds the individually set target, episodes of severe hypoglycaemia or wide daily variations in blood glucose concentration occur) with an appropriate multiple injection regime consisting of rapid-acting and long-acting insulin derivatives, the patient is referred for glucose sensor monitoring and for consideration of an insulin pump. In type 1 diabetes, blood pressure and blood lipids must also be in good control.