Marcelo Bosch starts at outside centre in place of Gonzalo Tiesi, who has been ruled out of the tournament after suffering knee ligament damage in the 13-9 defeat by England.
Martin Rodriguez moves from full-back to inside centre, allowing Santiago Fernandez to move to fly-half while Felipe Contepomi recovers from bruised ribs.
As a result, Lucas Amorisino starts at full-back and the Pumas will be captained by number eight Juan Martin Fernandez Lobbe for the seventh time.
Argentina have picked the same forward pack that dominated England for large parts of the opening game.
ARGENTINA: L Amorosino; G Camacho, M Bosch, M Rodriguez, H Agulla; S Fernandez; N Vergallo; R Roncero, M Ledesma, J Figallo, M Carizza, P Albacete, J Farias Cabello, JM Leguizamon, JM Fernandez Lobbe.
Replacements: A Creevy, M Scelzo, M Galarza, A Campos, A Lalanne, N Sanchez, J Imhoff.