The FTC last year received 161,800 identity theft complaints, up from 86,200 in 2001, according to its annual report on consumer fraud.
ID theft accounted for 43% of all fraud complaints. The number of fraud complaints overall increased by nearly 73%, from 220,000 to 380,000 and cost for all fraud reached $343m (£212m).
FTC officials said the increase may be partly because more victims have filed complaints, as well as increased participation from public and private agencies that report fraud.
But an independent survey released earlier this month by Star Systems found that one in 20 adults - about 11.8 million people in the US - have been victims of identity theft.
"That's a pretty huge number - it's something that could be considered epidemic proportions," said Barbara Span, a vice-president at Star.
"What is very telling is that 19.2% of the respondents said they personally know somebody who has been victimised. That's one in five adults," she said.
Jerry Brady, chief technology officer at Guardent, believed the threat is much greater, and said thieves may have thousands and thousands of stolen identities in reserve. There is increased awareness and reporting, but "reporting happens after... the actual crime".
Brady said companies needed to assess systems and put in robust and real detection systems, get monitoring in quickly, and assume the worse and do a post mortem. Many systems, particularly retail, remain vulnerable.
Credit card fraud was the leading method for identity theft, accounting for 24% of the complaints, and old accounts making up for 12% of the crimes.