If, however, the days roll by and the form is indeed lost or your employer is inordinately slow in issuing a replacement, or you worked for a company that went out of business and there's no one to bug about getting a W-2, what then?
Don't panic. You can re-create your W-2 on an IRS form and file that instead with your return.
Alert the IRS
First, find your last pay stub. You'll need the information shown there -- wages, Social Security and Medicare taxes paid, federal and, if applicable, state and local taxes withheld, any pension or 401(k) contributions -- to recreate your missing W-2.
The stub also should show the employer information: company name, address and possibly the employer identification number, or EIN. If the EIN isn't on a pay stub and you received a W-2 from the errant employer in prior years, the tax number will be on the old statements. You don't have to have the EIN, but it will help when the IRS processes your return.
Armed with this information, call the IRS at (800) 829-1040 for help in obtaining the missing form. The IRS will use the employment data you gathered -- along with your personal information, such as your Social Security number and dates of employment -- to remind your boss that you need a substitute W-2.
The IRS will send your boss a special form noting that you did not receive your W-2. You'll get a copy of that notice along with a Form 4852, Substitute for Form W-2, Wage and Tax Statement. If, even after nudging from the IRS, your employer doesn't send you a replacement W-2 in time for you to file your tax return, you may file using Form 4852 in place of your missing wage statement.
If you get your official W-2 after filing with the substitute form and its data is different from what you reported on your return, you need to refile. Do this by completing Form 1040X, Amended U.S. Individual Income Tax Return.
If you can't get through to the IRS, you can download Form 4852 from Bankrate's site or the IRS website and fill out the replacement wage statement yourself.
This one-page form, plus a page of instructions, walks you through the W-2 re-creation process. You'll also have to explain how you got the numbers you entered -- generally from old paychecks -- and describe the efforts you made to obtain your missing W-2. If you're missing multiple W-2s, you'll need a separate Form 4852 for each.
After you complete the form, attach it to your tax return in place of your absent W-2. A copy of Form 4852 also should satisfy your state tax collector for those returns. Be aware, though, that using Form 4852 instead of an original W-2 may delay your refund while the IRS verifies the information you provided.
And in cases where an employer has filed for bankruptcy or ceased operations, the IRS suggests you send a copy of Form 4852 to your local Social Security Administration office. The agency's office locator can help you find the one nearest you. This should ensure that you get proper credit for the Social Security and Medicare taxes you paid so that your checks will be correct when it comes time to collect these benefits.