Josh Adams and Hallam Amos grabbed tries each side of half time and Rhys Patchell kicked 20 points for Warren Gatland’s side to complete back-to-back wins following a 23-10 triumph over the home side last week.
Wales were the strongest side from the off and raced into a 19-0 lead thanks to Adams' try and four penalties from Patchell.
Bautista Delguy got a try back for Argentina moments before halftime but the Welsh tore in the Pumas again in the second half, with two quick penalties from Patchell and a converted try from Adams.
Julian Montoya put a more respectable sheen on the scoreline when he ran over for a try with the last move of the game and Nicolas Sanchez converted.
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The only blemish for Wales came in the dying seconds when Ross Moriarty was shown a red card for choking.
The result means that Argentina, who face Scotland next week, have won only two of their last 17 internationals.
(Writing by Andrew Downie, reporting by Ramiro Scandalo, editing by Pritha Sarkar)
