However, the amount spent per buyer witnessed a slight decline this year, it said.
"Following last year's disappointing performance when sales fell by 3 per cent, the e-commerce sector saw a positive 2009 holiday shopping season with sales up by 5 per cent," ComScore chairman Gian Fulgoni said.
Retail e-commerce spending for the holiday season from November 1 through Christmas eve was around $27 billion, which represents an increase of five per cent over the same period a year ago, ComScore added.
"Online sales growth this year was driven by a continued increase in the number of people buying online, but consumers economic challenges resulted in a slight decline versus last year in the amount spent per buyer," Fulgoni added.
However, after adjusting for the additional shopping day in 2009, sales grew by about 3.5 per cent, as per ComScore.
During the festive season this year, larger retailers significantly outperformed their smaller peers.
"In these tough economic times, the retailers with sufficient financial resources and a willingness to invest in aggressive marketing and free shipping offers were clear winners," Fulgoni said.
In terms of individual product categories, consumer electronics saw strong sales of over 20 per cent, while jewelry and watches also turned in a strong sales.
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