The Your Move Scotland Buy-to-Let Index said the strongest growth came in the Highlands & Islands region where average monthly rents were £610. This was 5.6% higher than a year ago.
The next strongest growth came in Edinburgh and Lothians where average rents were 4.5% up on the previous year, standing at £669 in September.
Glasgow and Clyde was the only region to record a reduction in average rents. Average monthly rents in September were £541, down 6% on a year earlier.
Brian Moran, lettings director at Your Move Scotland, said: “With four of the five regions of Scotland showing price growth in the last 12 months, things are looking up for Scottish landlords. Returns remain highly competitive and landlords are enjoying greater stability from their tenants. However, the upcoming introduction of the Letting Agent Code of Practice means landlords should ensure their agent is ready for the changes.”
The Letting Agent Code of Practice will come into force from 31 January 2018.
Letting agents will be required to join a Register of Letting Agents and Your Move Scotland urged landlords and property investors to ensure their agent will be compliant with the new rules.
The survey found that landlords saw a return of 4.8% in September, down on the 4.9% recorded during August. This is also down slightly on the 5% recorded during September 2016.