Gaylor: "They play by a different set of rules."

The Freedom from Religion Foundation has filed yet another federal lawsuit against the Internal Revenue Service.

The Madison-based group that advocates for the separation of church and state charges that the IRS gives preferential treatment to churches and other religious organizations by not requiring them to file the "detailed, intrusive and expensive annual reports to maintain tax-exempt status" that are required of other non-profit groups, including the Freedom From Religion Foundation itself.

Filed in the U.S. District Court for the Western District of Wisconsin, the lawsuit was brought on behalf of the foundation and a local chapter, Triangle Freethought Society, based in North Carolina.

Annie Laurie Gaylor, co-president of the Freedom from Religion Foundation, says that each year her group pays an accountant about $1,000 to complete the required Form 990. The form asks for detailed information on governance, management, disclosure practices, activities, revenue, expenses and financial results, the lawsuit notes.

These forms are considered public records and available online, says Gaylor. "Our main contention is that because of a lack of reporting and accountability [churches] are just off the hook," says Gaylor. "They play by a different set of rules."

If other non-profits don't file a 990 Form "there are penalties and you could lose" your tax-exempt status, says Gaylor.

The lawsuit alleges that the IRS is violating the Establishment Clause, among other constitutional rights. The plaintiffs ask the Court to prohibit the IRS from continuing to exempt churches from filing a Form 990.

The IRS does not comment on pending litigation.

Last month, the Freedom From Religion Foundation sued the IRS for failing to enforce electioneering restrictions on churches.

Read the full text of the lawsuit.