Depending on what you mean by bad. FHA requires at least a 620 credit score in most cases, stable stable and verifiable employment and a required debt to income ratio. I would suggest you contact a mortgage loan officer and have him/her pull your credit report and walk you through the steps of getting your credit score up to purchase a home.
On the other hand, some people don't have a credit score due to they don't borrow money and have paid cash for everything. If this is the case, you can get an underwriter to manually underwrite your loan for you as well. Hope this helps... more