Are churches required to register as 501(c)(3)s?

Summary:

Generally, no. But some organizations connected to churches do apply for recognition as tax-exempt by the IRS.

Someone wrote in Nonprofit (see http://www.rain.org/mailman/listinfo/nonprofit) in January 2004:
Most churches in America have organized as 'incorporated 501c3 tax-exempt religious organizations.' This is a fairly recent trend that has only been going on for about fifty years.

Surely this cannot be deliberate, but must be based upon gross ignorance of the law. It also seems to be based upon, 'Everyone else is incorporating and getting their 501c3. Guess we'd better do it too.' Just because everyone else is doing it, does that make it right?

Rob Shriner answered on January 13, 2004:
It is correct that churches do not have to apply for tax-exempt status in the
US or obtain classification as a 501(c)(3) to carry out their religious mission.
However, it is not correct that most churches do obtain 501(c)(3) status, though
many churches do apply for and obtain 501(c)3 status for their auxiliary
enterprises that conduct charitable activities that are essentially
non-religious in nature. This may make those 'charitable auxiliary
enterprises' eligible for support from certain foundations and other private
funding sources that do not donate to religious activities.

No "conspiracy", just fact.

In a discussion about how the IRS handles the possibility of abuse of tax-exempt status by organizations described as churches, Chip Watkins (Webster, Chamberlain & Bean in Washington, DC) wrote on 2/22/04:
That the Internal Revenue Code gives special treatment to churches is not
news. Since 1969, when Congress enacted Sec. 508, which requires all Sec.
501(c)(3) organizations to apply for exemption, churches have been exempt.
Same for Form 990 filing requirements in Sec. 6033. In 1984, after several
perceived abuses, Congress revised and made more specific a series of audit
protections for churches, now found in Sec. 7611.

These provisions simply recognize that religious freedom was one of the most
important reasons America was founded; that the free exercise of religion is
guaranteed against the Federal government by the First Amendment; that, as
Chief Justice John Marshall said (in a case involving the power of a state
to tax a federally chartered bank), "the power to tax is the power to
destroy;" and that while churches are subject to the Internal Revenue Code
generally, certain aspects of the Code and its administration present a
sufficient threat to the free exercise of religion that special rules to
protect churches are appropriate.

Does this leave the door open to abuse? Unquestionably. Have abuses
occurred? Of course. Are the abuses any more significant among churches
than other kinds of charities? Doubtful, especially considering the number
of churches relative to the number of other kinds of charities.

Moreover, the information thresholds required in order to begin a church
audit are not very high. They simply require that the IRS document that it
has reason to believe that the church MAY not be entitled to exemption or
that it MAY be subject to unrelated business income tax. (Sec. 7611 does
not apply to employment tax audits, during which information relative to the
other areas might be developed.)