Retrieving an old tax document of any kind can be difficult if you don’t know where to look, mainly because these types of documents contain personal and financial information about you, including your social security number. In many cases, you’ll need to be able to prove that you are in fact the person requesting the form before anyone who has it will relinquish it to you. Before you even begin to dial phone numbers or send request letters you’ll need to have your driver’s license or other personal ID ready, as well as be able to answer some questions.

There are a couple different methods to try when you need an old W2.
The first, and quite possibly the easiest method of recovering an old W2 form is to contact your employer at the time the W2 was issued.
Sometimes, however, you may not be able to contact a former employer, especially in cases where a business has gone bankrupt, is out of business or documents have been destroyed in fires or natural disasters. In these cases, you’re going to need to inquire with the IRS.
Before you even bother with the Internal Revenue Service, you should really make sure that you can’t locate the form on your own. If there’s a chance you may have a copy of it anywhere you may be able to locate it, search for it thoroughly before filing for a request with the IRS. You’ll want to do whatever you can to avoid the processing headache of requesting an old document from them, so make sure you’ve exhausted any other option.
If you do have to resort to requesting your W2 from the IRS, be aware that you may not even receive an actual copy of the document, but rather a transcript of the documentation, depending on the format submitted to the IRS by your employer.
So, now you know a few methods for how to get an old W2 form. To avoid having problems in the future, it is generally a good idea to keep tax records for up to seven years so you'll always have things on hand that you need. If you don't want all those papers sitting around your house (or if you want to make sure you can always find a copy) you may want to consider scanning such forms into your computer so you can have an electronic copy.