A civil war in the east of the country has been raging since 2014, and thousands of people have been killed.
Christians prayed for peace and thousands and stood together in solidarity in the capital Kiev.
Thousands of faithful gathered at the National Sports Palace in Kiev and Protestant, Catholic, Ukrainian and Russian Orthodox leaders all attended.
The group sang hymns together and asked God to unite their nation and end the fighting.
British evangelist David Hathaway organised the event and the day finished with prayers for Russia and President Vladimir Putin.
Ukraine's history and culture are very close to Russia's but disagreements about how closely the two countries should be linked have led to conflicts since the break-up of the USSR in 1991.
