Tax Due Dates

2009 income tax returns must be filed or extended for calendar-year corporations. If the return is not extended, this is also the last day for calendar-year corporations to make 2009 contributions to pension and profit-sharing plans.
If the monthly deposit rule applies, employers must deposit the tax for payments in February for social security, Medicare, withheld income tax, and nonpayroll withholding.

Last day to file (or extend) your 2009 personal return and pay any tax that is due. So are 2009 returns for trusts and calendar-year estates, partnerships, and LLCs, plus any final contribution you plan to make to an IRA or Education Savings Account for 2009. SEP and Keogh contributions are also due today if your return is not being extended.
First quarter estimated tax payments are due for individuals.
First quarter estimated tax payments are due for trusts.
First quarter estimated tax payments are due for calendar-year corporations.
If you need to file a 2009 gift tax return, it also must be filed or extended by this date.
If you paid cash wages of $1,600 or more in 2009 to a household employee, you must file Schedule H by this date. You may also have to report any federal unemployment tax paid and any income tax you withheld for your household employees.

If the monthly deposit rule applies, employers must deposit the tax for payments in April for social security, Medicare, withheld income tax, and nonpayroll withholding.