Deputies could be named and thrown out for not observing the new rule
The Dáil has voted to make it mandatory for TDs to stand during the prayer at the start of business each day.
Deputies face being named, thrown out and losing a day's pay if they refuse to observe the new rule.
A period of 30 seconds silent reflection has also been added to take place after the prayer and before business gets underway.
Back in March, an Oireachtas committee decided to keep the daily prayer in the Dáil and Seanad.
A number of opposition groups have previously called for the prayer - which was originally introduced in 1932 - to be scrapped.
The prayer says: "Direct, we beseech Thee, O Lord, our actions by Thy holy inspirations and carry them on by Thy gracious assistance; that every word and work of ours may always begin from Thee, and by Thee be happily ended; through Christ our Lord. Amen."
It is also said in Irish.
These people in Dublin have been giving their reaction to our reporter, Erin Breen.