Anthony Horgan of Munster goes over for his try against Ulster
Munster 21 (12)
Tries: Wallace, Horgan
Pens: O'Gara 3
Ulster 13 (13)
Pens: Humphreys 2
Title holders Ulster fell to their second defeat of the Magners League campaign with Munster claiming a deserved success at Musgrave Park.
Ulster had enjoyed a great start with David Humphreys stroking over a penalty and then converting a seventh-minute try scored by Paul Steinmetz.
David Wallace and Anthony Horgan got tries for Munster but Humphreys landed a penalty to have Ulster 13-12 ahead.
Three Ronan O'Gara penalties in the second half sealed the win for Munster.
It was a disappointing end for Ulster who had beaten Munster home and away last season.
Mark McCall's men raced out of the blocks with New Zealander Steinmetz cutting through to touch down under the posts for the opening try.
Humphreys did have a penalty chance to make it a 13-point gap but missed and the game swung the other way.
Wallace forced his way over, O'Gara added the conversion and the Heineken Cup holders were in business.
A man up after Justin Harrison was sin-binned, Munster got their second try on 27 minutes with Horgan going in on the right.
Humphreys restored Ulster's lead with a penalty three minutes before half-time but the northern province failed to score in the second half.
To make matters worse, O'Gara's last penalty near the end denied Ulster a bonus point.
Munster: Cullen, Horgan, Kelly, Payne, Dowling, O'Gara, Stringer, Horan, Kyriacou, Pucciariello, O'Callaghan, O'Connell, Quinlan, Wallace, Foley.
Replacements: Roche, T. Ryan, O'Driscoll, Hickey, O'Leary, Halstead, McGann, Lawlor, O'Meara.
Ulster: Bartholomeusz, Bowe, Steinmetz, Wallace, Trimble, Humphreys, Boss, J. Fitzpatrick, R. Best, B. Young, Harrison, McCullough, N. Best, McMillan, Wilson.
Replacements: Shields, D. Fitzpatrick, Barker, Ferris, Dawson, Campbell, Maggs.
Referee: Donal Courtney (Leinster)