Inclusion Criteria:

• Male and female patients with a diagnosis of type 2 diabetes mellitus
• HbA1c between 7% and 10%
• Age between 18 and 80 years
• BMI less than 40 kg/m2
• Signed and dated informed consent prior to admission to the study in accordance with GCP and local legislation

Exclusion Criteria:

1. Myocardial infarction, stroke or TIA within 6 months prior to informed consent
2. Impaired hepatic function
3. Renal insufficiency or impaired renal function
4. Disease of central nervous system, or psychiatric disorders or clinically relevant neurologic disorders that may interfere with trial participation
5. Chronic or clinically relevant acute infections
6. Current or chronic urogenital tract infection determined by medical history
7. History of clinically relevant allergy/hypersensitivity
8. Treatment with glitazones, GLP-1 analogues or insulin within 3 months prior to informed consent
9. Treatment with anti obesity drugs
10. Current treatment with systemic steroids
11. Alcohol abuse
12. Treatment with an investigational drug within 2 months prior to informed consent
13. Intolerance to metfomin
14. Dehydration
15. Unstable or acute CHF
16. Acute or chronic acidosis
17. Hereditary galactose intolerance
18. Woman of child bearing potential who are nursing or pregnant or not practicing an acceptable method of birth control