Absolutely...shows on your credit report as a debt, just as it would if it were your own loan. Also, the payment history shows on your report, if the person you co-sign for becomes deliquent in their payments..it will have a negative affect on your credit report. Also, it will affect your debt to income ratio. . . I'd be very cautious co-signing for anybody. Especially if you have any doubt that they will make timely payments!