This study will assess the safety and efficacy of adding nateglinide to treatment with basal insulin glargine, metformin and/or thiazolidinedione (pioglitazone or rosiglitazone), for patients with type 2 diabetes who are not achieving glycemic control with glargine, metformin and/or thiazolidinedione only.

Inclusion Criteria:

• Male/female, age 18-78 inclusive
• Type 2 diabetes, taking glargine, metformin and/or thiazolidinedione for 3 months prior to screening, stable doses for 2 months prior to screening
• HbA1c 7.0-8.5% inclusive
• Fasting plasma glucose <240 mg/dL at screening
• Body Mass Index 22-41 kg/m2

Exclusion Criteria:

• Pregnant or nursing
• Other investigational drugs within 30 days of screening
• Treatment with other anti-diabetic medications other than metformin, glargine and/or thiazolidinedione
• History of type 1 diabetes
• Abnormal kidney function
• History of acute diabetic complications
• Congestive heart failure requiring treatment
• Myocardial infarction, coronary artery surgery, stroke within 6 months of screening
• Liver disease, liver enzymes more than 3 times upper limit of normal
• Fasting triglycerides >700 mg/dL within past 12 weeks
• Acute infections or other conditions that may affect blood sugar or may interfere with interpretation of study data
• Treatment with corticosteroids
• Blood donation within past 12 weeks

Other protocol-defined inclusion/exclusion criterial may apply.