The term underground church (Chinese: 地下教会; pinyin: dìxià jiàohuì) is used to refer to Chinese Catholic churches in the People's Republic of China which have chosen not to associate with the state-sanctioned Catholic Patriotic Association; they are also called loyal church (Chinese: 忠贞教会; pinyin: zhōngzhēn jiàohuì).
Underground churches are also sometimes referred to as "Vatican loyalists" because they have attempted to remain loyal to the Pope and the Holy See.
There is no established organization structure of underground churches, though they tend to be clustered around a number of Vatican-ordained bishops.
[4]: 185 In 1989, underground churches formed the Bishops Conference of Mainland China (Chinese: 天主教中国大陆主教团; pinyin: Tiānzhǔjiào Zhōngguó Dàlù Zhǔjiào Tuán) as separate from the state-sanctioned Bishops' Conference of Catholic Church in China [zh] (Chinese: 中国天主教主教团; pinyin: Zhōngguó Tiānzhǔjiào Zhǔjiào Tuán), which was established in 1980.
[4]: 185 Benedict XVI stated that sacraments performed by the priests not in unity with the Vatican were valid but also illicit.