From the Internal Revenue Service
Most tax-exempt organizations, other than churches, must file a yearly return or notice with the IRS. If an organization does not file as required for three consecutive years, the law provides that it automatically loses its tax-exempt status. Loss of exempt status means an organization must file income tax returns and pay income tax, and its contributors will not be able to deduct their donations.
The Internal Revenue Service will soon publish and begin maintaining a list, updated monthly, of organizations that have had their federal tax-exempt status revoked. The Nonfiler Revocation List will be available in two formats, Adobe Acrobat and Microsoft Excel. The list will be divided into separate lists for each state, the District of Columbia, and all other territories and countries.
The list will provide, for each revoked organization, the name, Employer Identification Number, organization type (subsection code), last known address provided to the IRS by the organization, and the effective date of revocation. The effective date of revocation is the original filing due date, without regard to extensions, of the third annual required return or notice that was not filed.