Vrlo je uočljivo drastično smanjivanje broja katolika u Bosni i Hercegovini tijekom posljednjih 30 godina. Od 760.852, koliko ih je bilo 1991. godine, prema državnom popisu iz 2013. godine ostalo ih je 544.780, odnosno prema crkvenim procjenama na kraju 2018. na tom području bilo bi 365.688 katolika. Taj proces započeo je za vrijeme rata (1991. - 1995.) progonima i iseljavanjem zbog straha i nastavio se nakon toga zbog nesigurnosti, izostanka i onemogućavanja održivog povratka, novog iseljavanja i negativnog priraštaja. Katolička Crkva u BiH od 2003. do 2018. godine bilježi gubitak od 99.133 vjernika. Odnosno, Banjolučka biskupija je tijekom posljednjih dvadesetak godina ostala bez 45,71 % vjernika, koji su na njezinu području bili 1999. godine, Sarajevska je ostala bez 32,48 % u odnosu na 2002. godinu, Mostarska bez 11,75 % nakon 2006., a Trebinjska bez 13,04 % od 2005. godine. U tom općem gubitku vlastiti negativan priraštaj sudjeluje s 23.214, što znači da se iz BiH u tom razdoblju, prema crkvenim procjenama, iselilo 75.919 katolika. Ovaj rad podijeljen je u šest naslova: Okolnosti i zakonski okviri suvremene društvene zbilje u BiH, Depopulacija i denatalitet pogađaju cijelu BiH, Smanjivanje broja katolika ponovno postao proces, Negativan priraštaj i novo iseljavanje katolika, Uloga državne vlasti i međunarodne zajednice u traženju rješenja te Još neki izazovi Katoličke Crkve u složenom društvu BiH.; After the number of Croats and Catholics in B&H was almost halved at the end of 20th century due to war persecution and displacement, emigration and negative growth became their new major problem. According to church data, after surviving the war tragedy and an initial slight comeback after the war, with new emigration and negative growth, the Catholic Church in B&H from 2003 to 2018 registered a loss of 99,133 believers. In other words, during the last 20 years, the Diocese of Banja Luka has lost 45.71% of believers, who were in the diocese in 1999. The Diocese of Sarajevo has lost 32.48% compared to 2002. The Diocese of Mostar has experienced a loss of 11.75% after 2006. And finally the Diocese of Trebinje has lost 13.04% since 2005. In this general loss according to church estimates, 75,919 Catholics emigrated from B&H during that period resulting in negative growth of 23,214 people. The demographic decline of Catholics and Croats in B&H after the war is the consequence of many simultaneous causes. The most important among these are: lack of political and material support for the return of refugees and displaced persons; very negative natural growth; new emigration; high unemployment rates that encourage emigration in search of employment; political and legal uncertainty; corruption and frustration; new emigration as a consequence of plans by developed countries to replace their own demographic losses and to gain labour workers; insufficient social and material support for women who wish to give birth; the growing crisis of marital morality and secularization; a crisis of awareness among believers about the value of life and parental collaboration with the Creator God; young people leaving, and the high average age of the population, etc.