The push for the play-offs kicks off on Friday night, when second-placed Glasgow Warriors welcome Munster to Scotstoun Stadium.
A win at this stage is crucial for Munster who themselves are still chasing a top four finish; however Warriors have the prospect of a home semi-final to encourage them.
The two Welsh regions that are neck and neck for the fourth play-off position are in action at the Millennium Stadium on Saturday, but not against each other.
The Scarlets are first up on the double header bill when they take on Newport Gent Dragons, with the Ospreys following them with their game against Cardiff Blues.
There is more that pride at stake in these two Welsh derby fixtures, the Ospreys and Scarlets have been swapping fourth and fifth spot in the table since round 13 and are currently only separated by points difference, so every point is critical in their final push for the play-offs.
Long-time leaders Ulster, who have now dropped to third place, are gearing up for a very important tussle with current table toppers Leinster on Saturday evening.
With just one point separating the two provinces, victory for either side has the added bonus of denying the other, who are one of their main challengers for a home draw, the match points.
Also on Saturday, Connacht, who were held scoreless by Munster in last weekend's interpro derby, will be hoping to close the gap on Benetton Treviso when they visit the leading Italian club. Connacht lie ninth in the table, seven points behind Treviso.
RABODIRECT PRO12 - ROUND 19 FIXTURES:
Friday, March 29 -
Zebre (12th) v Edinburgh (10th), Stadio XXV Aprile, 7pm local time (live SportItalia 2/BBC ALBA)
Glasgow Warriors (2nd) v MUNSTER (6th), Scotstoun Stadium, 8.05pm (live TG4/BBC ALBA)
Saturday, March 30 -
Newport Gwent Dragons (11th) v Scarlets (5th), Millennium Stadium, 2.30pm (live BBC 2 Wales)
Cardiff Blues (8th) v Ospreys (4th), Millennium Stadium, 5.15pm (live S4C)
LEINSTER (1st) v ULSTER (3rd), the RDS, 6.15pm (live RTÉ Two/BBC 2 Northern Ireland)
Benetton Treviso (7th) v CONNACHT (9th), Stadio di Monigo, 8pm local time/7pm Irish time (live SportItalia 2)