The Istanbul-based Orthodox patriarch on Sunday handed over a formal decree confirming the creation of an independent Ukrainian church to its leader, Metropolitan Yepifaniy.
The decree was signed at a landmark ceremony on Saturday, putting the formal stamp on a break with the Russian Orthodox church which has infuriated Moscow.
The document was handed over by Patriarch Bartholomew during an Epiphany service at St George's Cathedral in Istanbul, an AFP correspondent said, completing the Ecumenical Patriarchate of Constantinople's recognition of the newly-independent Ukrainian church.
Ukraine's President Petro Poroshenko, who attended Saturday's signing ceremony, was also present for the mass.
Known as a Tomos decree, the document grants autonomy to the Ukrainian Orthodox church which until now has been overseen by Moscow for more than 330 years.
The decree opens the way for Ukraine's Orthodox Church to be recognised by other branches of orthodoxy and other churches.
The Constantinople Patriarchate, based in modern-day Istanbul and considered the first among equals in the Orthodox world, first agreed to recognise the independence of the Ukrainian Orthodox Church in October.
Then in December a historic council of Orthodox bishops in Kiev created the independent body and chose 39-year-old Metropolitan Yepifaniy as its head, whose secular name is Sergiy Dumenko.
He has been a long time critic of Moscow's religious influence in Ukraine.
The move has dealt a huge blow to Moscow's spiritual authority in the Orthodox world, prompting it to cut all ties with the Constantinople Patriarchate in protest.
Ukraine and Russia have been at loggerheads since 2014, when Kiev street protests calling for Ukraine's integration with Europe led to the fall of pro-Moscow president Viktor Yanukovych.
Russia subsequently annexed Crimea and has supported Russian-speaking separatists in Ukraine's east in a conflict that has claimed the lives of more than 10,000 people.
Ukraine is home to millions of believers who belong to the Orthodox Church, but their loyalties are divided between the Kiev and Moscow patriarchates.
Analysts said the ceremony was "the first step in a long road", indicating it was not clear which of Ukraine's bishops would choose to join the new church.