Governor Pat Quinn signed the bill into law Friday.
Recipients must submit a plan detailing firms owned by minorities, women, or persons with disabilities that will join in the work.
The plan requires state approval.
The House and Senate approved the bill unanimously.
"The legislation is very, very important for those businesses across Illinois that do get a state grant," said Quinn. "We want to make sure that they are complying with the mission of diversity, making sure that every business get a fair shot at competing for their particular work."
In Illinois' $35 billion capital program, $3 to $6 billion is expected to be available to firms with minority, women, and disabled owners.