The 16-page document was prepared by the Congregation for the Doctrine of the Faith, a doctrinal watchdog that Pope Benedict used to head.
Formulated as five questions and answers, the document is titled "Responses to Some Questions Regarding Certain Aspects of the Doctrine on the Church."
It says although Orthodox churches are true churches, they are defective because they do not recognize the primacy of the Pope.
The document adds that Protestant denominations — called Christian Communities born out of the Reformation — are not true churches, but ecclesial communities.
"These ecclesial communities which, specifically because of the absence of the sacramental priesthood … cannot, according to Catholic doctrine, be called 'churches' in the proper sense," it said.
The decree comes days after liberal Catholic and Jewish groups spoke out against the Pope's move to authorize the wider use of a traditional Latin mass.
The Tridentine mass includes a prayer for the conversion of Jews. Its use was restricted following the Second Vatican Council from 1962 to 1965.
Pope Benedict issued a decree last week authorizing its broader use in an effort to reconcile with followers of an ultratraditional excommunicated bishop." CBCnews
...and they worshipped the beast, saying, Who is like unto the beast? who is able
to make war with him? And there was given unto him a mouth speaking great things and blasphemies;
Revelation 13:4,5