This trial is conducted in the United States of America (USA). The aim of this trial is to evaluate the clinical performance of two formulations of insulin aspart (NovoLog®) in subjects with type 1 diabetes.

Inclusion Criteria:

• Subjects with type 1 diabetes treated with insulin for at least 12 months
• BMI (Body Mass Index) between 18.0-29.0 kg/m^2
• Negative fasting C-peptide (below or equal to 0.6 ng/mL)
• HbA1c (glycosylated haemoglobin A1c) below or equal to 10.0%
• Current treatment with insulin below or equal to 1.2 U/kg/day
• Subject should be in good health based on medical history, physical examination and routine laboratory data

Exclusion Criteria:

• Any known/suspected allergies to trial medication or similar products/devices
• A subject who has proliferative retinopathy or maculopathy, and/or severe neuropathy, in particular autonomic neuropathy, as judged by the Investigator
• Clinically significant active disease of any kind
• Recurrent major hypoglycemia or hypoglycemic unawareness, as judged by the Investigator
• Blood donation (more than 500 mL) within the previous 9 weeks