The state will buy the new cars over the next several months, and they're expected to be in use in July.
The Illinois State Police have said the average state patrol car has 122,000 miles on it, about 40,000 miles more than is recommended for state police fleets.
As a result, the high-mileage cars are breaking down, keeping troopers from responding quickly to accidents and costing millions of dollars annually in repairs.
Blagojevich's office says more than $15 million has been made available to purchase the cars through a capital appropriation.
After the cars are purchased, they'll be outfitted with emergency lights, radios, video cameras and new computers.