If it has been while since you updated your resume, you might be at a loss to remember the exact dates and addresses of your previous employers. You might also be applying for a job that requires a significant employment history. There are several ways to track down this information, depending on how much information you have, how much information you need and how much investigating you are willing to do.
Contact your previous employer's human resources department. If you already know the places you worked and just need more detailed information such as start and end dates, the company's human resources department is likely to have your information on file.
Check your old tax forms. If you've kept your tax records over the years, you can reference your W-2s to gather information about your past employment history. If you are missing any tax forms, you can call the Internal Revenue Service help line and ask for this information.
Order your detailed Social Security summary report from the Social Security Administration. To do so, you must fill out Form SSA-7050-F4, Request For Social Security Earnings. Be sure you indicate you are requesting a detailed report. There is a fee, and it can take several weeks to process, but it contains your entire employment history.
Conduct a public records search. This is especially useful if you were a school or government employee. Employment records for these people are public and anyone can request access to them. Your city's records department, or the university or school where you worked would have this information on file.
Hire a background-check company. Ordering your own background check brings up a list of previous employment. This option can be costly, but the results are usually delivered quickly and often instantly.