The latest SRC-KPMG Retail Sales Monitor has revealed Scotland's first fall in total sales for more than a decade.
Sales values were down by 0.3% on a total basis against March 2010, when sales had risen 3.9%, boosted then by Good Friday and Easter Saturday falling in the March trading period.
Like-for-like sales were 3.9% down, against a 0.6% increase in March 2010, the worst drop since January 2000.
Consumer concerns over jobs and incomes and the later Easter resulted in like-for-like food sales falling well below their year-earlier level, while and non-food sales also showed a much steeper fall of 5.9%.
Larger purchases of homewares and furniture purchases were hardest hit.
The Scottish Retail Consortium's director Fiona Moriarty said: "Reality is biting for Scottish shoppers. People are increasingly nervous about the economy and their personal finances and are reluctant to spend unless they have to. Food sales have slowed markedly while non-food sales have seen a much steeper fall.
Consumers in Scotland don't have the confidence to spend on large items for the home or buy in new fashion lines. Where they are spending, the focus is on bargains and price cuts. The current spell of warm weather and the approach of Easter offer some hope but it will take more than sunny bank holiday weekends to fundamentally change the gloomy retail outlook."