Coach Allen Clarke has named a strong side for the first game, with the spine of team drawn from the squad that finished second in this year's RBS Under-20 6 Nations.
Brian O'Hara and Nevin Spence, who played in the Ireland Under-20 Development side's win against France in April, have made the starting line-up in addition to Jonny Shiels who was capped for Ireland Under-19s last season.
Spence and Shiels form an exciting, all-Ulster centre partnership, with Blackrock College and Leinster's Ian Madigan adding experience at full-back having played in last year's Junior World Championship in Wales.
Cork Constitution and Munster's Peter O'Mahony will again lead the team from number 8.
Speaking earlier this week, Clarke said: "Our success in the Six Nations was built on an ethic of hard work, good attitude and a tremendous spirit within the team.
"We won a lot of close games, three stand out, and that in itself tells you when you come out the other end that you've got something special to work with."
Commenting on Friday's opponents, he added: "I've watched Argentina on video. They're certainly a physical side and like all Argentinian sides, they're going to challenge you around the fringes. But they've got the flair too.
"Obviously the first game is our focus at the moment. But it's only one game of three in our pool stages and one game of five in the whole tournament."
IRELAND UNDER-20 TEAM & REPLACEMENTS (v Argentina Under-20s, IRB TOSHIBA Junior World Championship, Mizuho Rugby Ground, Nagoya, Friday, June 5, kick-off 5pm local time/9am Irish time):
15 - Ian Madigan (Blackrock College/Leinster)
14 - David Kearney (Lansdowne/Leinster)
13 - Nevin Spence (Ballynahinch/Ulster)
12 - Jonny Shiels (Queen's University/Ulster)
11 - Michael Keating (Clontarf/Leinster)
10 - Ian McKinley (UCD/Leinster)
9 - Matthew Healy (Lansdowne/Leinster)
1 - Paddy McAllister (Ballynahinch/Ulster)
2 - Thomas Sexton (Old Belvedere/Leinster)
3 - Jack McGrath (St. Mary's College/Leinster)
4 - Ciaran Ruddock (Neath/Exiles)
5 - Mark Flanagan (UCD/Leinster)
6 - Dominic Ryan (Lansdowne/Leinster)
7 - Brian O'Hara (UL Bohemians/Munster)
8 - Peter O'Mahony (Cork Constitution/Munster) (capt)
16 - David McGregor (Ballynahinch/Ulster)
17 - Adam Macklin (Belfast Harlequins/Ulster)
18 - Joe Moran (Galwegians/Connacht)
19 - David O'Callaghan (UCC/Munster)
20 - Conor Murray (Garryowen/Munster)
21 - Andrew Burke (Garryowen/Munster)
22 - Eamonn Sheridan (Lansdowne/Leinster)