The Greek Catholic Church (also called the Uniate Church) was established in 1596 by the Union of Brest-Litovsk. That agreement brought several million Eastern Orthodox Belorussians and Ukrainians under the authority of the Roman Catholic Church, although they preserved Orthodox religious rites. From the outset, many in the Orthodox Church strongly opposed Latinization and what they perceived as the compromise of tradition, and conflict between the Greek Catholic Church and both the Polish Catholic Church and the Orthodox Church flared periodically into the early 1990s. In Poland the tense relations between proponents of the Latin and the Greek Catholic rites had relaxed significantly in the 1980s, although serious issues remained unsolved. Among the foremost of those issues was Catholic occupation of Greek Catholic Church property confiscated by the state in the late 1940s.

In 1947 the resettlement of the Ukrainian population from southeastern Poland substantially reduced the practice of Greek Catholicism in Poland. In 1949 Pope Pius XII appointed Wyszynski as the papal delegate to the Greek Catholic congregations of Poland. In 1956 Wyszynski named sixteen Ukrainian priests as the clerical body of the Greek Catholic Church, and a vicar general was also named and installed in Przemysl. In 1981 Glemp named two vicars general for Warsaw and Legnica to improve the church's ministry to the dispersed Ukrainian Greek Catholic communities. Beginning at that time, church administration was divided into northern and southern districts. In 1989 the total membership of the Greek Catholic Church in Poland was estimated at 300,000, with eighty-five centers of worship and fifty-five priests. Twelve candidates were preparing for the Greek Catholic priesthood at the Catholic University of Lublin in 1989 five monasteries and three orders of nuns were active.

Data as of October 1992