East Dundee and Countryside fire crews responded to the area of Rock Road Drive and Route 72 just after 11:15 a.m., for a reported three-vehicle crash.
When crews arrived they found two vehicles were heavily damaged.
RELATED: Pontiac father, son killed in Thanksgiving Day crash identified: officials
One person was extricated from each severely damaged vehicle, officials said.
One person was taken to Sherman Hospital with critical injuries, and another was taken to Saint Alexis Medical Center with life-threatening injuries, fire officials said.
It was not immediately clear what led up to the crash.
East Dundee police are investigating.