The purposes of this study are to determine: 1. If patients taking insulin lispro LM with metformin will have better overall control of their blood sugar than patients taking a long acting insulin comparator with metformin. 2. If there is a difference in the way the two treatments affect blood sugar control before and after meals and at night. 3. If there is a difference in the insulin dose required with the two treatments. 4. If there is a difference in the numbers of times patients experience low blood sugar with the two treatments. 5. If there is a difference in the effect on patients's body weight.

The aim of the present study is to compare two treatments - LM twice daily plus metformin two or three times daily versus a long acting insulin comparator once daily plus metformin two or three times daily - in patients with type 2 diabetes who are currently using a regimen of one or more oral antihyperglycemic agents.

The primary objective of this study is to demonstrate that, in patients with type 2 diabetes who are new to insulin, hemoglobin A1c at endpoint will be lower after treatment with insulin lispro LM twice daily plus metformin than after treatment with a long acting insulin comparator once daily plus metformin.

This will be a multicenter, randomized, open-label, crossover study comparing twice-daily insulin lispro LM plus two- or three-times-daily metformin to a once-daily long acting insulin comparator plus two- or three-times-daily metformin in patients with type 2 diabetes who were receiving one or more oral antihyperglycemic agents without insulin prior to the study.

Following an 8 (+-2) week lead-in period consisting of treatment with NPH once daily at bedtime plus metformin two or three times daily, approximately 100 eligible patients will be randomized to one of two sequence groups, so that there are approximately 50 patients in each group. One group will receive 4 months of insulin lispro LM administered immediately before the morning and evening meals plus metformin two or three times daily followed by 4 months of a once-daily long acting insulin comparator at bedtime plus metformin two or three times daily. The other group will receive the reverse sequence.

Inclusion Criteria:

• Type 2 diabetes.
• At least 30 years old and less than 80 years old.
• Using oral agents without insulin for 30 days prior ot study.
• Willing to start insulin injections using a pen device.
• Keep a patient diary.

Exclusion Criteria:

• Undergoing therapy for cancers.
• History of renal transplant or receiving renal dialysis.
• Have participated in an interventional medical, surgical, or pharmaceutical study (a study in which a medical or surgical treatment was given) within 30 days prior to entry into the study.
• Women who are breastfeeding.
• Have been treated with a drug within the last 30 days that has not received regulatory approval.