Retail sales volumes increased by 3.7% on an annual basis in January, new figures from the Central Statistics Office show.
But retail sales were down 3.4% on a monthly basis following strong sales in December that last year included the "Black Friday" deals period.
The CSO said that when volatile car sales are excluded, the volume of retail sales decreased by 1.8% on a monthly basis and were 2.9% higher on an annual basis.
Retail sales grew by 2.1% in 2019 as a whole, the slowest calendar year growth since 2013 when a rapid economic recovery began to take shape in the country.
Today's figures show the sectors with the largest monthly decreases included Motor Trades, with sales in the industry down 11%.
Sales of Hardware, Paints and Glass were also 6.6% last month.
Meanwhile today's CSO figures also reveal a decrease of 1.4% in the value of retail sales in January when compared with the previous month.
There was an annual increase of 3.5% when compared with January 2019.