For the 17th consecutive month, retail sales in Scotland lagged behind the UK which recorded a 1.6% increase during August.
SRC economist Richard Lim said: "The Olympics were spectacular but didn't produce the much-needed boost to Scottish retail sales. Sales were down on a year ago and even more than they were in July.
"Some sectors suffered less than others. Food sales growth was noticeably better in August than in July. The Games helped sales of party food and drink but the hot spell in the middle of the month dampened demand for autumn and winter clothing ranges arriving in stores.
"On balance, any gains were more than cancelled out by a big year-on-year drop in sales of non-food goods, which compounded another large fall a year earlier."
While the Olympics created a "feelgood factor", it was also a "major distraction from shopping", Mr Lim said.