March 15th, Deadline for corporate tax returns (Forms 1120, 1120A, and 1120S), or to request automatic 6-month extension of time to file (Form 7004).

Final deadline to file an amended corporate tax return (Form 1120X) for tax year 2007 and still claim a tax refund.

Efile Form 7004 through http://www.ExtensionTax.com for just $9.99 and get easy 6-month extension of time to file certain Corporate Income Tax form 1120, 1120A, 1120 S.