Q. 1. What is the teaching of the Catholic Church regarding freemasonry? Can Catholics join this organization?
A. 1. The Catholic Church prohibits membership to the freemasonry organization that is secretive and anti-Catholic and whose principles are totally incompatible with the revealed Truths of the Catholic Faith.
During the history of the Catholic Church, eight popes have issued a serious condemnation of its tenets and practices beginning with Clement XII in 1738. His constitution was confirmed and renewed by Benedict XIV.
In 1980, the Sacred Congregation for the Doctrine of the Faith reaffirmed that the Catholic Church has not changed its position regarding freemasonry. It declared:
"..the Church’s negative position on Masonic associations ..remains unchanged since their principles have always been regarded as irreconcilable with the Church’s doctrine. Hence joining them remains prohibited by the Church. Catholics enrolled in Masonic associations are involved in serious sin [meaning mortal sin] and are not to approach Holy Communion.
In the United States in 1985, the National Conference of Bishops called Freemasonry "irreconcilable with Catholicism" because the "principles and basic rituals of masonry embody a naturalistic religion active participation in which is incompatible with Christian Faith and practice. Those who knowingly embrace such principles are committing a serious sin."
To answer your question, Catholics cannot associate in any way with Masonic associations.