The objectives of this study are to characterize the pharmacodynamic profile, safety and tolerability of ONO-5129 in patients with Type 2 Diabetes mellitus

Inclusion Criteria:

1. Type 2 Diabetes Mellitus
2. FBG level > 140 mg/dL and < 270 mg/dL
3. Fasting TG level < 500 mg/dL
4. BMI of 22 to 40 kg/m2, inclusive
5. Other Inclusion criteria as specified in the study protocol

Exclusion Criteria:

1. Previous participation in an ONO-5129 protocol
2. Previous treatment with TZD agents or other current antidiabetics
3. History of myocardial infarction, coronary artery surgery, atrial/ventricular tachycardia, or atrial/ventricular fibrillation in the past six months
4. Presence of functional limitations due to cardiovascular disease in accordance with the New York Heart Association Classification System - Class III (moderate) or IV (severe)
5. Other exclusion criteria as specified in the study protocol