Typically, eligibility for unemployment benefits starts on the date you file for unemployment benefits. This means that waiting to file for benefits usually means that you will not get paid for the weeks in between the time you become unemployed and the time you file for unemployment benefits. However, in some instances, your unemployment benefits can be retroactive, which allows you to claim earlier benefits. This determination is done on a case-by-case basis.

Apply for your unemployment benefits as soon as you can because the longer you wait means the longer you may have to wait for benefits to start. In order to attempt a retroactive claim for weeks before your application, you must apply for benefits over the phone and ask the representative to backdate your claim. When you do this, you will be given an address to which to send your appeal for backdating. Employment history details for the previous 18 months are needed to complete the application for unemployment benefits.

Write a letter detailing why you are requesting the backdating of your unemployment application. Typically you need a solid reason for why you could not file on time, such as the unemployment agency filing system's being down or overwhelmed. Valid reasons vary by state, with some states allowing backdating if your employer did not inform you of your right to file for unemployment.

Send your letter to the address you were given by the unemployment claims center representative. Include any supporting documentation that you have so that it can be reviewed with the letter. Usually this letter needs to be in the mail within 10 days of your initial application, so as to not delay your benefits determination.