The purpose of this clinical research study is to learn if BMS-512148 is effective in controlling blood sugar levels as determined by HbA1c and fasting plasma glucose in patients who have been diagnosed with Type 2 diabetes. Patients should first try to control their diabetes with diet and exercise and should not have previously been treated for their diabetes (very short periods of time are acceptable). The safety of BMS512148 will also be studied

Inclusion Criteria:

• Patients with Type 2 diabetes mellitus with inadequate glycemic control on diet and exercise. HbA1c >= 7% and <=10%.
• Patient either has not been previously treated with antihyperglycemic medication or has been treated for <30 days since diagnosis and has received less than 3 consecutive doses or 7 non-consecutive doses in the last 30 days.
• C-peptide > 1.0 ng/ml
• Body Mass Index <= 40 kg/m2
• Serum creatinine < 1.5 mg/dL for men or < 1.4 mg/dL for women.
• No overt proteinuria (microalbumin/creatinine ratio must be <300 mg/g

Exclusion Criteria:

• Unstable renal disease
• Patients with significant liver disease including chronic active hepatitis
• Within the last 6 months has had any of the following cardiovascular event: myocardial infarction, unstable angina, unstable CHF,NYHA Class III or IV CHF, TIA, unstable arrhythmia or cardiac revascularization surgery.
• Subjects with clinically significant anemia