It was the first time the Scots had beaten the Pumas on their own patch in a full international and ended a run of seven successive defeats over the past 18 years against the world's third ranked team.
Record breaking full back Chris Paterson celebrated winning his 88th cap, and move ahead of Scott Murray to stand alone as Scotland's leading cap holder, with a 16 point match haul.
Paterson's four penalties joined tries from Ross Ford and Graeme Morrison, both of which he converted. The Scots were 16-0 ahead at half-time and were good value for their win.
The Pumas scored a try in the last minute by Horacio Agulla to eventually cut the deficit to 12 points. The Scots had hoped to pick up extra IRB ranking points by winning by 15 points or more, but were still delighted with their triumph.