24 Hour Plasma Glucose Profiles Comparing Lispro Mix 75/25 vs. Glargine

Inclusion Criteria: * Have type 2 diabetes * Have inadequate overall glycemic control (hemoglobin A1c greater than or equal to 7.0% and less than or equal to 12.0%) at or within 4 weeks prior to Visit 1 * Have used: * single or multiple OAMs for at least 3 months immediately prior to entering the study, including metformin, sulfonylurea, meglitinides (repaglinide, nateglinide), or alpha glucosidase inhibitors (acarbose, miglitol); or * insulin (once or twice daily) for at least 3 months immediately prior to entering the study; or * a combination of the above. * Are greater than or equal to 21 and less than 80 years of age * As determined by the investigator, are capable and willing to: * comply with their prescribed diet and medication regimen, * perform self blood glucose monitoring, * use the patient diary as required for this protocol, * participate in two 24 hour inpatient assessments Exclusion Criteria: * Have used a thiazolidinedione (pioglitazone or rosiglitazone) during the 3 months prior to entry into the study * Are currently treated with a meglitinide without sulfonylurea * Have a known allergy or intolerance to insulin lispro mix 75/25, insulin glargine, or metformin * Have plasma creatinine greater than or equal to 1.5 mg/dL (for males) or greater than or equal to 1.4 mg/dL (for females) for patients who will be treated with metformin or; greater than 2 mg/dL for patients treated with other OAMs, as determined by a local laboratory * Have received chronic (lasting longer than 2 weeks), systemic glucocorticoid therapy (excluding topical and inhaled preparations) within 4 weeks immediately prior to Visit 1