Edinburgh and Connacht are also in action on Friday night, with Connacht looking for a rare Scottish victory to mark their best start to a season since the 2002/03 campaign.
The remaining four fixtures all take place on Saturday with games in Italy, Ireland and Wales.
The action starts in Italy with the Ospreys heading to Benetton Treviso's Stadio di Monigo. The second-placed Ospreys will be anxious to continue their winning ways against the Italian outfit, and know that should other results go there way, they could find themselves top of the table by Saturday night.
Leinster are next into action when they take on Glasgow Warriors at the RDS. The province are building a formidable reputation at home having won their last 28 matches in all competitions at the Dublin 4 venue.
The record books do not favour Glasgow claiming a first ever win on Leinster soil.
Attention then switches to Wales where the Newport Gwent Dragons host Aironi. Neither team have tasted success so far this season, however Aironi did pick up a losing bonus point in their game against Ulster last time out.
Reigning champions Munster bring the round to a close when they play the Scarlets at Musgrave Park. The province secured a tournament record twelfth successive win last weekend, and will be hoping to make it 13 on Saturday.
RABODIRECT PRO12 - ROUND 3 FIXTURES:
Friday, September 16 -
ULSTER v Cardiff Blues, Ravenhill, 7.05pm (live BBC 2 Northern Ireland/BBC 2 Wales)
Edinburgh v CONNACHT, Murrayfield, 7.30pm
Saturday, September 17 -
Benetton Treviso v Ospreys, Stadio di Monigo, 3pm
LEINSTER v Glasgow Warriors, the RDS, 6pm
Newport Gwent Dragons v Aironi Rugby, Rodney Parade, 6.30pm (live S4C)
MUNSTER v Scarlets, Musgrave Park, 7.45pm (live TG4)