“I have a vendor who has asked that we send them a corrected 1099 for the year 2008. How do we go about correcting information on a 1099 for the year 2008 and can we even do that?”--> As his 1099-MISC is wrong he needs to get an amended copy right away. He can do this by notifying the paying company, you, that the 1099 you sent does not match his records. By law the company, payer, is required to investigate his claim and send him a new 1099-MISC if there were changes made. There is never a wrong time to do the right thing. As long as the government has records of receipt of gross income, then it is your duty to rebut the wrong evidence, no matter how old it is, because sooner or later, they will use it to come back to you and demand that you either file or pay. You need to create a corrected 1099-MISC (check the corrected box at the top of the form) and send the recipient their copy.Then you submit the corrected form to the IRS using Form 1096. The 1096 form has instructions for how to fill it out for corrected statements.