All three major credit rating agencies have labeled Illinois' financial outlook a "negative." Fitch issued its downgrade Friday. Fitch blames its action on lawmakers' failure to pass a pension overhaul before adjourning Tuesday.
The investor service surveys states' finances, and judges their ability to pay back debt.
Lower ratings could result in Illinois having to pay higher interest when it takes out credit for things like infrastructure projects, or other types of borrowing.
House Republican Leader Tom Cross says that's money Illinois doesn't have.
He calls the downgrade "embarrassing."
Governor Pat Quinn's assistant budget director issued a statement saying the Fitch report should be "required reading for every member of the new General Assembly."
Despite Quinn's urging, legislators have been unable to agree on a way to cut the state's pension costs.
Unions are fighting attempts to cut retirement benefits state employees have earned and were promised, though they've offered to require workers pay more into their pensions.