The games will take place on the first weekend in April
Leinster and Munster will face familiar opposition in the last 16 of the Investec Champions Cup.
Leo Cullen's men will look to repeat Saturday's 27-10 victory over the Leicester Tigers when the sides meet again in the knockout stages in Dublin.
Meanwhile, Graham Rowntree's charges will be looking for revenge when they go to the Northampton Saints.
Elsewhere, Ulster and Connacht have discovered their fates in the Challenge Cup.
The Westerners will travel to Pau in the last 16 while Ulster make the trip to Montpellier.
All those games will take place on the first weekend in April.

IRFU Investigate Online Racist Abuse Directed Toward Edwin Edogbo
Farrell Hits Out At "Keyboard Warriors" Aiming Abuse At Suncroft's Sam Prendergast And Jack Crowley
Monday Morning Sports Update
Kildare Football Team vs Derry
Tottenham Set To Appoint Igor Tudor As Interim Head Coach
Two League Of Ireland Games Postponed Due To Weather Conditions
ROI Begin Their National League Campaign Away To Kosovo On September 24th
Friday Morning Sports Update