It is now mid May 2013 and I just received a notice of 2009 property tax audit - has the statute of limitations expired?

Please stop asking the same question.

The Statute has expired. If you are uncertain, call the County Tax Assessor (assuming that's what you are talking about) and ask. In my area once you PAY taxes on the new assessment your time to appeal dies.

Idon't believe the OP is asking about filing an appeal on his tax bill, but rather has received notice of an upcoming audit - probably to ensure that his personal declarations as to improvements made to the property are valid - and is asking if he couold be subject to an audit so many years after he paid his taxes.

To the OP - I'm sorry I don't have specifics about property tax audit statute of limitations in MN, but I do know that in MN the state income tax statute of limitations is 3-1/2 years from the due date (which for tax year 2009 puts it at 3-1/2 years after April 15 2010, or October 2013). I realize that property taxes are a county matter, so the law is most likely different. For other states such as CA the statute of limitations on property tax is 4 years. But in most (perhaps all?) states the statute doesn't apply if fraud is involved.

Satutes may vary by county, so what county is this for?