If I agree to co sign a loan, will I be subject to a credit check, or just income verefication?

I've been asked to co sign a loan for a friend (in the state of texas, if it makes any difference). I meet the income requirements to do so, but my credit is not exactly spotless. Will my low credit score be reflected on my friends application? Obviously he has bad credit as well since he needs a co signer, but I don't want to waste his time (and his money, as he has to pay to have my name on his application) if my credit will be checked and it could prevent him from getting what he needs anyway.