Srednjovjekovna i potridentska teologija žrtvu mise, pričest i štovanje euharistije izvan mise promatrala je odvojeno. Saborski i posaborski crkveni dokumenti vraćaju se ispravnoj teološkoj tradiciji Crkve te euharistijski misterij počinju promatrati jedinstveno i cjelovito. Za takav pristup posebno je značajna Uputa o štovanju euharistijskog misterija Eucharisticum Mysterium Sv. Kongregacije obreda iz 1967. godine. Ova Uputa, premda u biti ne donosi ništa novo, ovaj misterij promatra na jedinstveni način u njegovoj cjelini, te u organičkoj sintezi na jasan način prikazuje, povezuje i hijerarhijski svrstava sva glavna teološka načela o euharistijskom misteriju. Euharistijsko slavlje, kao memorijal, žrtva i gozba zajedno sačinjava srž euharistijske realnosti u Crkvi, gdje su žrtva i sveta gozba međusobno najtješnje povezane. Pričest vjernika u misi i od te mise bitni je dio svake mise. I pričest, koja se iz opravdanih razloga prima izvan mise, proizlazi iz mise i vodi k misi, jer omogućuju vjernicima da se sjedine s Kristovom žrtvom koja se slavi u misi. Klanjanje i poklonstveno štovanje, koje se iskazuje Isusu u euharistijskim prilikama izvan mise, temelji se na valjanu razlogu i usmjereno je prema misi. Uputa jasno ističe da je euharistijska žrtva vrelo i vrhunac bogoštovlja i kršćanskog života i da je ona stoga u središtu, u polazištu i u cilju svega euharistijskog štovanja. U skladu s ovim postavljenim teološkim načelima Uputa izvodi pravila o teološki ispravnom načinu svih oblika štovanja euharistijskog otajstva. Autor u ovom radu, analizirajući ovu Uputu, želi pokazati da je ona zaista jedinstveni euharistijski dokument, jer na ovako jasan, cjelovit i teološki točan način crkveni nauk o euharistijskom misteriju nije bio prisutan u nekom crkvenom dokumentu prije ove Upute. Autor kritički argumentirano pokazuje da načela i duh ove Upute velikim dijelom još uvijek nisu zaživjeli u liturgijskoj praksi Crkve u Hrvata i ujedno pokazuje što bi trebalo učiniti da se to konačno i dogodi. Ova Uputa do sada kod nas nije prikazana na ovako sustavan i cjelovit način. U tome je izvornost i vrijednost ovoga rada., The sacrifice of mass, the holy communion and the worship of Eucharist apart of mass were regarded as separate units by the medieval and post-Trident theology. The II. Vatican council and post-council church documents have returned to the right theological tradition of Church and started viewing the mystery of Eucharist integrally and wholely. For such an approach, the Instruction on Observing Mystery of Eucharist- Eucharisticum Mysterium of St Congregation rite from 1967 is of special importance. This Instruction, though essentially bringing along no news, observes this mystery in a unique manner in its entirety and it also, in an organic synthesis and a clear way, presents, connects and hierarchically groups all the cardinal theological principles on Eucharist mystery. The celebration of Eucharist as a memorial, sacrifice and a meal at the same time, is the core of Eucharist reality in Church, where he sacrifice and the holy feast are mutually tightly connected. The believers' communion during the mass and of that mass is the essential part of every mass. Even the communion received for valid reasons apart of mass, arises from the mass and leads to the mass, because it enables the believers to unite with Christ's offering celebrated during the mass. Adoration and reverent worship, rendered to Jesus in the Eucharist form apart of mass, is founded on a good reason and oriented toward the mass. The Instruction clearly emphasizes that the Eucharists sacrifice in the source and culmination of religious observance and Christian life. Consequently, it is the central, initial and final aim of Eucharist worship. - According to these theological principles, the Instruction puts forward the rules on theologically correct way of all forms of worshipping of Eucharist mystery. Analyzing this Instruction, the author wants to point out the importance of this unique Eucharist document, since no other church document has ever presented the church teaching on the Eucharist mystery in such a clear, integral and theologically correct way. The author, in a critically argumented manner, indicates that the principles and spirit of this Instruction are yet to take hold in liturgical practice of the Church in Croatia, and he also points out what should be done for this to become a reality. So far, the Instruction has never been presented by us in such a systematic and coherent way. In this respect, this work is authentic and valuable.