Captain Brian O'Driscoll dives over for Leinster's first try
Leinster 27 (17)
Tries: O'Driscoll 2, Horgan, Heaslip
Cons: Contepomi 2
Munster 20 (10)
Tries: Wallace, Horan
Cons: O'Gara 2
Pens: O'Gara 2
A record league attendance of 27,252 at Lansdowne Road saw Leinster claim the bragging rights over Munster.
Brian O'Driscoll and Shane Horgan went over for tries to give Leinster a 17-10 interval advantage over Munster whose try was forced over by David Wallace.
A second try from O'Driscoll and a further score by number eight Jamie Heaslip secured Leinster's bonus point.
But Munster claimed a bonus as well by reducing the gap to seven as Ronan O'Gara converted Marcus Horan's try.
O'Driscoll got his side on the march by shrugging off the challenge of Jeremy Manning to waltz in from the left for a 13th-minute try.
Contepomi converted and after a spell in the sin-bin, added the extras to Horgan's effort on the half hour.
The Puma's only penalty of the night pushed Leinster 17-3 in front before Munster flanker Wallace dived over in the left corner.
It was certainly game on with O'Gara's superb conversion leaving it 17-10.
But Munster's hopes took a nosedive when they had prop Horan sin-binned within a minute of the restart.
O'Driscoll then darted in for his second try and a 22-10 Leinster lead.
O'Gara offered up a penalty in reply but Leinster battled to their second win in seven days with Contepomi's pass out to the right putting Heaslip over on 77 minutes.
There was still time for Horan to make use of a close-range penalty and tee up a bonus point-clinching conversion for O'Gara.
Leinster: G Dempsey, S Horgan, B O'Driscoll, G D'Arcy, D Hickie, F Contepomi, C Whitaker; R McCormack, H Vermaas, W Green T Hogan, M O'Kelly, S Keogh, K Gleeson, J Heaslip.
Replacements: R Corrigan, B Blaney, O Finegan, C Jowitt, G Easterby, C Warner, L Fitzgerald.
Munster: J Manning, I Dowling, J Kelly, T Halstead, T O'Leary, R O'Gara, P Stringer, M Horan, F Sheahan, F Puciariello, D O'Callaghan, P O'Connell (capt), A Quinlan, D Wallace, A Foley.
Replacements: T Ryan, A Kyriacou, M O'Driscoll, D Leamy, T McGann, B O'Meara, B Murphy.