That would depend on what kind of oral medication you were taking. Some diabetes medications (metformin, the TZDs) reduce insulin resistance, so it would make sense to keep taking them because it would mean you'd need less injected insulin.   But the sulfonylureas just make your own pancreas produce more insulin, and it doesn't make sense to me to keep taking them if you're injecting insulin.   Sometimes price is a factor. You may have to try different combinations and decide on the one that works best for your own individual case.   However, different doctors have different approaches to medications, so what you're actually prescribed may differ depending on the doctor. If you really don't like what your doctor is telling you to take, you can try to find another doctor whose approach is closer to yours.