NEW YORK (CNN/Money) - The number of people falling victim to identity theft has soared, as the Internet continues to prove a lucrative breeding ground for shady operators who steal millions from unwitting victims.

Those are the findings of the Federal Trade Commission, which in 2003 received more than half a million complaints from consumers who lost more than $437 million in crimes ranging from I.D. theft to sham Web auctions and bogus business opportunities.

For the third year in a row, identity theft topped the list of complaints with the FTC, according to the agency's annual Consumer Complaint Report released Thursday. Forty-two percent of victims -- or some 215,000 individuals -- reporting the crime.

"The most common complaint is the misuse of a person's identity to get a new credit card," said Howard Beales, director of the FTC's Bureaus of Consumer Protection. But crooks have also appropriated identities to obtain benefits, government documents or open bogus accounts.

Additionally, more than 300,000 other consumer fraud complaints were filed by victims who lost a median $228. The most common complaint came from individuals who were ripped off in bogus Internet auctions. Phony shop-at-home sales -- in which costs may not have been disclosed or goods weren't delivered -- followed next on the list.

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This was the first year that the FTC starting tracking crime statistics by metropolitan areas and the 2003 report found that the city with the highest rate of fraud was Washington, D.C., followed by Seattle and San Diego.

When it came to I.D. theft, most complaints came from Phoenix, Los Angeles and Riverside California, though FTC officials stressed that it's unclear if those areas top the list because they really have elevated levels of crime or simply because residents in those cities file more complaints at www.ftc.gov.

The statistics do, however, "reveal several significant stories about American consumers and American commerce," according to Beals.

Most significantly, the Internet has proven a fruitful way to reach victims. Of all the complaints filed, 55 percent involved the Internet, with crooks using e-mails and web site ads to soliciting individuals for money and sensitive personal information.

Those who found themselves victims of a crime had often been enticed by deals that seemed too good to be true. Four percent of consumer fraud complaints came from individuals who were swindled in so-called foreign money offers, which invite victims to loan money to fraudsters posing as foreign government officials.

Just as many individuals paid advance fees for guaranteed loans that never materialized, worthless credit card protection or a promise to have negative information removed from their credit reports.