The agency says weak holiday sales and lower sales of new cares pushed the decline.
Lower sales were reported in seven of 11 subsectors, representing 58 per cent of all retail trade.
Sales at motor vehicle and parts dealers were off 6.4 per cent, with a 7.7 per cent drop in new car sales.
Most store types typically associated with holiday shopping registered weaker sales in December, with general merchandise store receipts off 3.7 per cent.
Retail sales were down in all provinces in December, with Ontario reporting the largest decrease in dollar terms, at 2.4 per cent.