The study, which was conducted by the Future Foundation, found the total value of the Scottish direct marketing industry to be £2.97bn, with businesses in the country allocating an average 67% of their direct marketing expenditure on consumer activity, and the remaining 33% on business-to-business.
The Future Foundation said the Scottish direct marketing industry employed around 90,000 people, accounting for 3.7% of the country's total workforce, with the average annual industry wage standing at £27,300.
The report, which was commissioned by the DMA, found that the employment figure is "proportionally higher" than the UK as a whole, despite businesses in Scotland allocating less of their budgets to direct marketing.
In addition, the report said that 10% of Scottish businesses outsourced their direct marketing, while the figure for the rest of the UK stood at nearly 20%.
The Future Foundation said small- to medium-sized businesses with a turnover between £1m and £5m appeared to spend the heaviest amount on direct marketing proportionally.
The comparatively lower amounts spent by larger businesses were attributed to the tendency of bigger companies to fulfil the majority of their direct marketing budget "using internal resources".
Yvonne Balfour, chair of the Direct Marketing Association Scotland, said: "The research findings paint a picture of a dynamic industry which makes a significant contribution to the Scottish economy.
"However, to sustain such growth, it is vital that the industry continues to adapt and takes a responsible approach by balancing consumer and business needs with environmental and social responsibility."
The study, which analysed the economic effects of the direct marketing industry, comprised original research covering a representative example of 418 Scottish-based businesses.