Jenkins will face Argentina for the sixth time this weekend and will feature in the front-row alongside Ospreys hooker Richard Hibbard and Rhodri Jones (Scarlets) who replaces the injured Adam Jones. The Scarlets prop made his debut for Wales last summer against the Barbarians and featured on the summer tour to Japan. He will earn his third test-cap at the Millennium Stadium.
Bradley Davies (Blues) and Alun Wyn Jones (Ospreys) continue their partnership in the second-row.
In the back-row Ospreys flanker Justin Tipuric comes into the side for the injured Dan Lydiate. Lydiate injured his ankle in the defeat to the Springboks and has been ruled out of the second autumn tie. Tipuric will play at openside flanker with captain Sam Warburton (Blues) switching to blindside. The duo are joined by Toby Faletau (Dragons), reuniting the back-row which faced England in the final RBS 6 Nations game earlier this year and which saw Wales retain the Champions in dramatic style at the Millennium Stadium.
The 78-times capped Mike Phillips (Unattached) and Dan Biggar (Ospreys) who started all five of Wales' Six Nations games together in 2013 are named as the half-backs. Scarlets centre Scott Williams lines up alongside debutant Allen in midfield.
The back-three is the same that started the game against South Africa last time out with George North (Northampton Saints) and Liam Williams (Scarlets) on the wing and Leigh Halfpenny (Blues), who passed the 300 point-haul for Wales last weekend, at full-back.
"Last weekend will stand us in good stead in terms of physicality and intensity as Saturday will be a huge battle against Argentina," said Wales Head Coach Warren Gatland.
"They will be looking for a repeat of last year and we will need to be more clinical to get the result we are aiming for.
"We have been working hard to ensure we convert the chances we create and encourage the players to look for and exploit opportunities and space.
"Saturday will be a huge occasion for Gethin (Jenkins) and a fantastic milestone.
"We have made a number of changes due to injury but it's a great opportunity for players we have been very impressed with. For Cory (Allen) it will be his first taste of international rugby and for Rhodri (Jones) a chance to gain more experience. Justin (Tipuric) played very well off the bench last weekend and Dan's injury gives him the chance to start the game.
"At fly-half it was always our intention to give Dan (Biggar) and Rhys (Priestland) one game each at the start of the series and it's Dan chance this weekend."
Uncapped Scarlets prop Samson Lee lines up on the bench and he takes his place alongside fellow front-row replacements, hooker, Ken Owens (Scarlets) and, prop, Paul James (Bath). The bench also features Perpignan second-row Luke Charteris and the experienced, 73-times capped, Ryan Jones (Ospreys). Lloyd Williams (Blues), James Hook (Perpignan) and Ashley Beck (Ospreys), who all featured from the bench last weekend, are also named in the twenty-three.
WALES TEAM v ARGENTINA:
Leigh Halfpenny (Blues), George North (Northampton Saints), Cory Allen (Blues), Scott Williams (Scarlets), Liam Williams (Scarlets), Dan Biggar (Ospreys), Mike Phillips (Unattached), Gethin Jenkins (Blues), Richard Hibbard (Ospreys), Rhodri Jones (Scarlets), Bradley Davies (Blues), Alun Wyn Jones (Ospreys), Sam Warburton (Blues - CAPT), Justin Tipuric (Ospreys), Toby Faletau (Dragons).
Replacements: Ken Owens (Scarlets), Paul James (Bath), Samson Lee (Scarlets), Luke Charteris (Perpignan), Ryan Jones (Ospreys), Lloyd Williams (Blues), James Hook (Perpignan), Ashley Beck (Ospreys).