To investigate the performance of a software-algorithm based insulin therapy to control blood glucose in Type 1 diabetic patients.

Inclusion Criteria:

• Male or female aged 18 to 75 years (both inclusive)
• Informed consent obtained after being advised of the nature of the study
• The subject has Type 1 diabetes (as defined by WHO) for at least 24 months
• The subject's HbA1c <= 10%
• Body Mass Index (BMI) <= 35 kg/m2
• The subject is treated with continuous subcutaneous insulin infusion for at least 3 month

Exclusion Criteria:

• Subject is actively enrolled in another clinical trial or took part in a study within 30 days
• Experienced recurrent severe hypoglycaemic unawareness
• Total daily insulin dose >= 1.4 IU/kg
• Subject is using a medication that significantly impacts glucose metabolism (oral or topical steroids) except if stable for at least the last three months and expected to remain stable for the study duration
• Allergy against insulin Lispro
• A history of drug or alcohol dependence
• Any other significant concomitant disease such as endocrine, cardiac, neurological, malignant, other pancreatic disease or uncontrolled hypertension as judged by the investigator
• Uncontrolled hypertension with resting blood pressure over 140/90 mmHg
• Patient is pregnant, or breast feeding during the period of the study
• Patient donated blood in the last 3 months