Munster are ahead of the Ospreys and Leinster at the top of the table. They travel to Rodney Parade to face the Newport Gwent Dragons on Saturday evening, looking for a fifth straight win over their hosts.
It is all very tight behind the leading three teams and should the Dragons upset the leaders they could move up the table from seventh place by the end of the weekend - if other results go their way.
Also amongst that chasing group, the Scarlets, Edinburgh and Glasgow Warriors are all equal on 26 points, with the Scarlets and Edinburgh meeting on Sunday.
The Scots have won six of their last seven fixtures against the Scarlets, and will be eying fourth place with a win on their first visit to Parc y Scarlets.
Glasgow Warriors face a trip to Ulster, looking for a fourth straight win over the northern province as they aim to stay with the pace.
The rounds final game sees 'the bottom two sides, Connacht and Cardiff Blues, face off in Galway on Friday.
MAGNERS LEAGUE - ROUND 12 FIXTURES:
Friday, March 6 -
CONNACHT v Cardiff Blues, The Sportsground, 6.30pm
Ospreys v LEINSTER, Liberty Stadium, 7.05pm (live BBC Wales/Setanta Sports Ireland)
Saturday, March 7 -
Newport Gwent Dragons v MUNSTER, Rodney Parade, 5.30pm (live S4C/Setanta Sports 1)
ULSTER v Glasgow Warriors, Ravenhill, 7.30pm (live Setanta Sports 1)
Sunday, March 8 -
Scarlets v Edinburgh, Parc y Scarlets, 4.10pm (live S4C)