This trial is conducted in Europe and South America. The aim of this trial is to compare the glycaemic control of insulin detemir plus insulin aspart with that of insulin NPH plus human soluble insulin in subjects with type 1 diabetes on a basal/bolus regimen.

Inclusion Criteria:

• Type 1 diabetes for at least 12 months
• Current treatment with any basal/bolus regimen or any biphasic insulin treatment for at least 6 months
• BMI below or equal to 35 kg/m^2
• HbA1c below or equal to 12%

Exclusion Criteria:

• Proliferative retinopathy or maculopathy requiring acute treatment
• Recurrent major hypoglycaemia that may interfere with trial participation (as judged by the Investigator)
• Subjects with known hypoglycaemic unawareness as judged by the Investigator