Check your mail! Medicare is mailing out new cards to all Medicare beneficiaries. The old Medicare cards are on their way out primarily because they use Social Security numbers as identifiers. The new numbers are randomly assigned numbers and letters to help prevent fraud. The cards will arrive in the mail and you do not have to order or pay for them. Beware of scammers who call and ask for payment for the new cards. The government is mailing the cards directly to you and many beneficiaries in Arizona have already received them.