A green card affirms your status in the United States as a lawful permanent resident. The law requires you to keep your green card with you at all times. Otherwise, you could face misdemeanor charges.
However, green cards eventually expire and need replacing. Other circumstances can also arise that require you to replace it ahead of schedule. The United States Citizenship and Immigration Services explain how to replace your green card and some reasons why it might be necessary.
How to replace your green card
If you are a lawful permanent resident and you are in the United States when you need to replace your green card, you can apply for a replacement by filling out and submitting Form I-90. You can mail in a paper form, or you can submit it online. If you are outside the United States when your card expires, you should contact the nearest USCIS office, port of entry or U.S. Consulate for information prior to Form I-90 submission.
If the USCIS denies your application, you have the right to appeal. Otherwise, you will receive your new green card in the mail following approval of your application.
Why you may need to replace your green card
Apart from the periodic expiration of your green card, there are other reasons why you might need to replace it. If you never received your original green card, or it became mutilated, lost or stolen, you need a replacement. You also need to replace your green card if the information on it is not accurate or if your information changes, e.g., you change your legal name. A change in status can also necessitate a green card replacement. For example, if you are a permanent resident becoming a commuter, or vice versa.