Odnosi Katoličke Crkve i države od Drugoga svjetskog rata pa sve do kraja osamdesetih godina prošlog stoljeća prolazili su kroz različita razdoblja. Položaj Katoličke crkve i drugih vjerskih zajednica u FNRJ i SFRJ bio je uređen Ustavom iz 1945., 1963., i 1974. godine, te odgovarajućim zakonima o pravnom položaju vjerskih zajednica. Područje „vjerskih sloboda“ u Jugoslaviji bilo je strogo pod nadzorom države. Komunistički režim neprijateljski se odnosio prema vjerskim zajednicama, a osobito prema Katoličkoj Crkvi. Katoličkoj crkvi ograničeno je djelovanja, oduzeta imovina, nametnuti porezi, brojni svećenici su nevini ubijeni ili osuđeni bez suda i suđenja, na kazne zatvora, a među njima i kardinal Alojzije Stepinac. To je dovelo do prekida diplomatskih odnosa, sve do potpisivanja Protokola između Svete Stolice i SFRJ 1966. godine. Iako je komunistički režim pokušavao suzbiti rad Crkve, ona je kontinuirano djelovala, osobito na župama. Đakovački i srijemski biskup Stjepan Bäuerlein početkom šezdesetih godina osniva nove župe na području Osijeka, među njima i župu Bezgrešnog Začeća BDM, danas župu sv. Leopolda Mandića. Početak rada župe bio je težak, nije bilo sigurnih financijskih sredstava, naselja u kojima se nalazi župa nisu bila u potpunosti izgrađena, a gradska vlast nastojala je blokirati svaki korak Crkve. U takvim uvjetima župa je uspjela uspostavile svoje pastoralno djelovanje upornim radom i strpljivošću prvog župnika o. Zvonka Marije Pšaga.

Relations between Roman Catholic Church and the State have been passing through many periods since World War II and 1980’s. Position of Catholic Church and other religious organisations in the Federal People's Republic of Yugoslavia and the Socialist Federal Republic of Yugoslavia was arranged by The Constitution in 1945, 1963 and 1974, and appropriate laws concerning legal position of religious organisations. The status of „religious freedom“ in Yugoslavia was strictly under the state's supervision. Communist regime was unfavorable to religious organisations, especially towards Catholic Church. There were limiting actions, confiscated property, imposed taxes, numerous innocent priests killed or convicted without trial, amongst them was cardinal Alojzije Stepinac. That lead to termination of diplomatic relations up until the signing of the Protocol between The Holy See and SFRY in the year 1966. Although Communist regime tried to repress operations of the church, the church continued to operate, especially through parishes. During the early sixties, ordinary bishop of the Diocese of Ðakovo and Srijem, the Most Reverend S. Bauerlein, opened new parishes in the Osijek. One of them was The church of The Immaculate Conception of the Blessed Virgin Mary, which is today known as The church of the saint Leopold Mandić. The beginning of parish's activity was tough. There was no financial stability, settlements within the parish weren't fully completed and settled, furthermore city government sought to block every attempt of church leaders. In those conditions the parish managed to establish pastoral activity by persistent work and patience of the first parish’s priest father Zvonko Marija Pšag OFM Cap