There were seizure orders for 150 Internet domain names for businesses selling counterfeit goods, the Justice Department said in a statement.
Cyber Monday, a one-day shopping event, was created by companies to persuade people to shop online as a followup to the Black Friday sales crush.
The Departments of Justice and Homeland Security joined the FBI Washington field office in cracking down on sales of "a host of products," including professional sports jerseys, golf equipment, DVD sets, footwear, handbags and sunglasses, the statement said.
"Through this operation, we are aggressively targeting those who are selling counterfeit goods for their own personal gain while costing our economy much-needed revenue and jobs," Attorney General Eric Holder said.
Authorities announced it was "the eighth phase of Operation In Our Sites," which is a "sustained law enforcement initiative to protect consumers by targeting counterfeit and piracy on the Internet."
It is the second year Operation In Our Sites has focused on Cyber Monday, the Justice Department said.