The Six Nations champions had gone 11 end-of-year tests without a home victory, but they ended that run in clinical fashion against the Pumas despite having two players sent to the sin-bin.
Mike Phillips and George North scored first half tries, while Leigh Halfpenny kicked 13 points in the opening period.
Argentine flyhalf Nicolas Sanchez did pull a penalty back for the visitors, but it was Wales who led 23-3 at the break.
Halfpenny and Sanchez traded penalties at the start of the second period, before Toby Faletau and replacement hooker Ken Owens touched down.
Welsh kicking sensation Halfpenny converted both tries and another penalty to take his personal haul to 20 points.
Wales, who lost 26-12 at home to Argentina last year, dominated possession early and got the game’s first try when scrumhalf Phillips, without a club after being sacked by French club Bayonne, stole the ball from the grasp of flyhalf Sanchez and raced 80 metres to score.
Soon after, Wales, whose last home win at this time of year came against Argentina in 2009, were reduced to 14-men when Justin Tipuric was yellow-carded for a trip.
A further penalty extended their lead and with Tipuric back on the field Wales went further ahead as flying winger North touched down after a surging run.
Halfpenny’s boot kept the scoreboard ticking over and with Wales dominant on the counter-attack, the hosts produced another incisive breakaway as Faletau collected Liam Williams’s precision pass to extend the lead to 33-6.
Argentina looked beaten and they yielded their fourth try of the afternoon when their defence could not contain a catch-and-drive move from a lineout, allowing replacement hooker Owens to bundle his way over for his first try in a Welsh jersey.
(Writing by Michael Hann, Editing by Justin Palmer and Josh Reich)