Will a Debt Management Plan affect my credit rating?

The debt management plan itself will not show on your credit file however, this does not mean you credit record will not be damaged. Unless you make the full, contractual payments to all your lenders, adverse information will be recorded on your credit file. Under the terms of your debt management plan, it is likely you will be paying less than the contractual payment to each lender; the reason for entering an arrangement is that you were unable to afford those payments. In that case, your credit file is very likely to be damaged.