U.S. Marshal Service spokesman Thomas Volk says that prison officials discovered 64-year-old Michael Krzyzaniak and 67-year-old Gerald Greenfield were missing during a prison count Saturday night.
The prison camp is on the former Duluth Air Force Base north of the city. Volk said prisoners there are "on the honor system" instead of having locked cells.
Krzyzaniak is serving a 12-year sentence for bilking investors out of nearly $26 million.
Greenfield is serving a four-year sentence for conspiracy to commit money laundering in a $2.5 million mortgage fraud scheme.
Anyone with information about the men can contact the U.S. Marshal Service or call 911.