The issue of apostolic succession is one of the subjects of ecumenical dialogue between the Roman Catholic Church and the Polish-Catholic Church in the Republic of Poland. Thanks to studies conducted in this area, it is possible to ascertain the preservation in the Polish-Catholic Church of the historical succession, originating through the Churches of the Union of Utrecht from the Roman Catholic Church. A difference, howewer, is the approach of the two communities to the succession of the episcopal ministry outside the community of the Church. The Old Catholic Churches, and hence the polish-catholics, do not recognise the validity of episcopal ordinations conferred outside the ecclesial community and without a specific mandate to confer them, even if the proper rite of conferral has been observed. The Roman Catholic Church, while regarding the conferral and reception of episcopal orders without papal nomination as giving rise to excommunication, nevertheless recognises their sacramental effect if the substance, form and proper intention of the conferral have been preserved.