Officials in New York seized "privileged communications" between Cohen and his clients, his lawyer said in a statement after the raid.
The FBI has raided the offices of US President Donald Trump's personal lawyer Michael Cohen, seizing "privileged communications" with his clients.
The 51-year-old is under investigation over possible bank fraud, wire fraud and campaign finance violations, according to people close to the case.
Cohen has been at the centre of a controversy surrounding the payment of adult film star Stormy Daniels, who has alleged that she had sex with Trump and was paid money shortly before the 2016 election to keep quiet about it.
Cohen's lawyer, Stephen Ryan, confirmed in a statement that a raid had taken place on Monday.
"Today the US Attorney's Office for the Southern District of New York executed a series of search warrants and seized the privileged communications between my client, Michael Cohen, and his clients," he said.
"I have been advised by federal prosecutors that the New York action is, in part, a referral by the Office of Special Counsel, Robert Mueller," Ryan said of the raid, which was first reported by The New York Times.
Mueller is investigating suspected Russian meddling in the 2016 presidential election. Russia has denied allegations that it interfered in the vote, and Trump and the White House have repeatedly denied any collusion.
In his statement, Ryan said the decision by the US Attorney’s Office in New York to conduct the investigation using search warrants was "completely inappropriate and unnecessary" as Cohen had "cooperated completely with all government entities, including providing thousands of non-privileged documents to the Congress and sitting for depositions under oath."