Shoppers spent £5.46 million online in December, a record high, according to IMRG Capgemini e-Retail sales index.
The figures show an average of £88.93 was spent by every person in the UK which is 17% higher than that spent in December 2008.
Sales rose 3.8% from November 2009 which shows typical monthly growth.
The second week in December was the most popular week for online Christmas shopping, which was a week later than in 2008.
James Roper, Chief Executive of IMRG comments: "The latest Index figures prove yet again that online shopping thrives on adversity. The sector managed to deliver strong double-digit growth in 2009 despite the economy being in recession, aggressive high street competition, extreme weather and even postal strikes in the run-up to Christmas.