Defending Magners League champions Munster, are also at home on Friday night, and welcome Edinburgh to Musgrave Park.
The Scots are one of only two teams not to have their campaign disrupted by the weather last time out; the points they gained from that match lifting them to third position - two places above Munster in the table.
Victory for Tony McGahan's men, who have not lost at home for over 12 months, would see them leapfrog over Edinburgh in the table.
Finally on Friday night, the Cardiff Blues make a second successive trip to Scotland, this time to face the current league leaders, Glasgow Warriors, at Firhill.
The Warriors have led the league since they took over top spot after round 8, however there is only a five-point difference, or a bonus point win, between the first and fifth-placed sides in the table, so they will be keen to keep racking up the points, and with Cardiff's poor away record, must be targeting this game as a home victory.
On Saturday European champions Leinster welcome the Scarlets to the RDS, a ground where the hosts have not lost a Magners League game since September 2008.
Occupying the last play-off spot, Leinster have two games in hand over their near rivals, but will be eager to take every opportunity to secure match points.
Their Llanelli-based visitors, finding themselves at the wrong end of the table, do not have a good record in Ireland but have not lost on the road in the Magners League since October.
The last game of the round sees Connacht travel to Swansea to face the Ospreys at the Liberty Stadium, a ground where the visitors have never tasted success.
The Ospreys are currently the leading Welsh region in the league and will be hoping for a victory to keep the pressure on table-topping Glasgow.
MAGNERS LEAGUE - ROUND 12 FIXTURES:
Friday, February 19 -
ULSTER v Newport Gwent Dragons, Ravenhill, 7.05pm (live Setanta Sports Ireland/BBC Wales)
Glasgow Warriors v Cardiff Blues, Firhill Arena, 7.30pm
MUNSTER v Edinburgh, Musgrave Park, 8pm (live Setanta Sports 1)
Saturday, February 20 -
LEINSTER v Scarlets, The RDS, 6.30pm (live Setanta Sports 1/S4C)
Sunday, February 21 -
Ospreys v CONNACHT, Liberty Stadium, 5pm (live Setanta Sports Ireland/S4C)