The helicopter was traveling from Rockford Memorial Hospital to pick up a patient in Mendota Monday when it crashed about 25 miles south of Rockford, the Chicago Sun-Times reported Tuesday.
The helicopter was destroyed, and all three people on board died, Federal Aviation Administration spokesman Tony Molinaro said.
Rockford Health System identified the victims as the pilot, Andy Olson, and flight nurses Jim Dillow and Karen Hollis.
No patients were aboard, Rockford Memorial Hospital spokesman Wester Wuori said.
"At Rockford Health System, our hearts are heavy," the hospital said in a statement posted on its website. "We grieve the loss of three heroes who dedicated their careers to serving others."
The helicopter was the hospital's only aircraft, and was used in Rockford Memorial's Regional Emergency Acute Care Transport program, the Sun-Times said.
An FAA team will assist in the investigation of the crash, Molinaro said. The investigation will be led by the National Transportation Safety Board.