1. Men and women who have had either type 1 or type 2 diabetes (World Health Organization[WHO]classification)for at least 2 months and are between the ages of 18 and 70 (inclusive) at the signing of the informed consent. 2. Have been treated with commercially available human insulin mix 50/50 or human insulin mix 30/70 twice daily as the only pharmacological treatment for their diabetes for at least 2 months prior to entering the study. 3. Have an HbA1c between 1.1 and 1.7 times the upper limit of the normal reference rang(inclusive) as determined by a local laboratory within 2 weeks prior to or at Visit 1. 4. Have achieved compliance with their diets and insulin therapies as determined by the investigators and perform regular blood glucose monitoring. 5. Have given informed consent to participate in this study in accordance with local regulations. [clinicaltrials_resource:0e83558ae3c2f696a0a99777ece22844]