If you've ever wondered about the logic behind Medicare's overpayment recovery system, CMS finally spells it out clearly in a new brochure entitled The Medicare Overpayment Collection Process. Essentially, if your MAC finds that it overpaid you by $10.00 or more, it will initiate the overpayment recovery process, which begins with a demand letter requesting payment. If you don't respond within 30 calendar days after that letter's date, the MAC may send a second letter. If the MAC doesn't receive full payment within 40 calendar days of the first demand letter, it will recoup your overpayment from future claims that you submit. In cases where you don't pay back the overpayment and the MAC does not recoup it, the contractor can send an Intent to Refer letter indicating that it can refer the overpayment to the Department of Treasury for collection. You are eligible to rebut or appeal the demand letters, or set up a repayment plan if necessary. For details on this process, visit www.cms.gov/MLNProducts/downloads/OverpaymentBrochure508-09.pdf.