Names of people authorized to own guns would be declared secret under legislation approved by the Illinois House.
The state police would be barred from releasing information on people who have Firearm Owner Identification cards.
The House approved the bill 98-12 Friday. It now heads to the Senate.
The attorney general ruled last month that the list of people with FOID cards must be released under the state Freedom of Information Act.
Firearm advocates objected. They argue the information would tell criminals who owns guns that are worth stealing.
The bill would allow disclosure of names in criminal investigations.