Republicans on the House Ways and Means Committee asked federal tax authorities Friday to look into AARP's finances.
The request was widely expected after the committee released a report last week raising questions about the hundreds of millions of dollars the nonprofit seniors' lobby gets for endorsing insurance products.
"The facts laid out in our report strongly suggest that AARP, Inc., and its affiliates may no longer qualify as a tax-exempt organization," said the letter to IRS Commissioner Douglas Shulman.
AARP says all its revenue supports its mission of helping seniors.
And Democrats say Republicans are simply trying to punish the seniors' lobby for putting its considerable weight behind healthcare reform.