It claims that crimes such as phishing and identity fraud cost retailers an estimated £205.4m in 2011-12 and now poses the biggest emerging threat to the sector.
Personal identification-related fraud is the most expensive type of e-crime for shops and produced £20m of losses in 2011-12.
This was followed by card fraud, which accounted for £15m losses in the same period.
Overall, e-crime represents 0.75 per cent of the £28bn of online retail sales in 2011. However, this is twice as much as the cost of retail crime as a proportion of total retail sales of £303bn.
The BRC said businesses still lacked confidence to report on crime, with more than 60 per cent questioned saying it was unlikely they would report any more than 10 per cent of e-crimes to police.