When was the ending date to file 2010 tax returns?

IF you filed for an Automatic Extension back on April 15th of 2011 then you could have waited until October 15th to file the 2010 return as a "current year" return.

However there is no Statute of Limitations for the filing of ANY year tax return. So if you failed to file your 1999 federal income tax return and the IRS finds out somehow that you had sufficient taxable income to file a return for that year then they are legally obligated by Congress to prepare a Substitute For Return for you. The SFR will allow ALL the income but not allow ANY deductions EXCEPT your Standard Deduction and your Personal Exemption amount for that year. IF in a previous year you filed as Married Filing Jointly then they will give you the Married Filing Separately status. If not, then they will give you the Single status.

So IF you have yet to file your 2010 return you can still file it. You likely will NOT be able to file it electronically; however you can still submit an "ink-on-paper" version.

The Statute Of Limitations for filing a "Claim" is three years from the original due date of the return OR two years from the date the tax was paid for that return. So if you are due a refund on your 2010 return go ahead and get it filed. If you wait past April 15th of 2014 then your refund/credit will be lost.