The All-Welsh European Challenge Cup quarter-final between Newport Gwent Dragons and Cardiff Blues will be played at Rodney Parade.
Dragons will host Blues on the first weekend of April, ending discussion on switching to the Millennium Stadium.
Martyn Hazell, Dragons chairman, said: "The players have worked very hard to earn home advantage so it doesn't make sense to throw that away."
Hazell expects a "great occasion" with the loud backing of their fans.
Easter falls on the weekend of the game and football club Newport County are already scheduled to host Hartlepool in League Two on Friday, 3 April.
That would preclude Thursday, 2 April as an option for Dragons v Blues, leaving Saturday, April 4 and Sunday, April 5 as potential dates for the rugby match.
Ahead of the announcement he was "delighted" to make, Hazell said of the Millennium Stadium option: "There's nothing worse than if you went to a big stadium with 15,000 or 20,000 people rocking around in an empty bucket."
The draw for the knockout stages was based on finishing positions in the pools, with Dragons seeded third - claiming home advantage - and Blues sixth.