Cape Town - South Africa's Jaco van Heerden will referee the South African Super Rugby derby between the Cheetahs and Lions in Bloemfontein on Saturday.
Van Heerden will be assisted by Jaco Peyper and Lourens van der Merwe, with Marius Jonker the Television Match Official (TMO).
In the later game at Newlands between the Stormers and Rebels, South Africa's Stuart Berry will be on duty.
Berry will be assisted by Quinton Immelman and Rodney Boneparte, with Deon van Blommestein on TMO duty.
Meanwhile, New Zealand's Chris Pollock will referee the Bulls' match against the Chiefs in Rotorua on Friday, with Australia's Angus Gardner appointed for the Sharks' game against the Reds in Brisbane.
Round 15 Super Rugby referee appointments:
Friday, May 22
Chiefs v Bulls, Rotorua - 09:35
Referee - Chris Pollock
AR1 - Glen Jackson
AR2 - Aki Aso
TMO - Glenn Newman
Reds v Sharks, Brisbane - 11:40
Referee - Angus Gardner
AR1 - Matt O'Brien
AR2 - Damien Mitchelmore
TMO - Peter Marshall
Saturday, May 23
Blues v Hurricanes, Auckland - 09:35
Referee - Nick Briant
AR1 - Ben O'Keeffe
AR2 - Aki Aso
TMO - Aaron Paterson
Waratahs v Crusaders, Sydney - 11:40
Referee - Marius van der Westhuizen
AR1 - James Leckie
AR2 - Michael Hogan
TMO - Peter Marshall
Force v Highlanders, Perth - 13:45
Referee - Andrew Lees
AR1 - Rohan Hoffmann
AR2 - Graham Cooper
TMO - Ian Smith
Cheetahs v Lions, Bloemfontein - 17:05
Referee - Jaco van Heerden
AR1 - Jaco Peyper
AR2 - Lourens van der Merwe
TMO - Marius Jonker
Stormers v Rebels, Cape Town - 19:10
Referee - Stuart Berry
AR1 - Quinton Immelman
AR2 - Rodney Boneparte
TMO - Deon van Blommestein