The Senate Homeland Security and Governmental Affairs investigations subcommittee released a letter late Friday inviting Mr. Galloway to appear and informing him that his comments would be under oath as sworn testimony.
The committee is examining evidence purporting to show that Mr. Galloway and a senior French politician received vouchers to sell millions of barrels of oil to reward them for supporting Saddam Hussein's regime in Iraq.
The committee has released documents from Iraq's Saddam-era oil ministry that identify the two men as voucher recipients, and say that the politicians sought to conceal the transactions.
Mr. Galloway has denied the allegations and had offered to testify in U.S. hearings. The Washington Times newspaper reports he will appear in Washington next week.
Some information for this report provided by AFP and AP.