The U.S. District Court for the Northern District of Illinois put out a statement on Thursday. It says it will draw names of potential jurors at random from driver's license and voter-registration lists.
Until now, authorities relied only on voter registrations. Critics argued that meant minorities were underrepresented.
The district's first Hispanic chief judge, Ruben Castillo, is implementing changes approved last year. He will send a new mailing of 34,000 qualifying questionnaires to would-be jurors.
Castillo became chief judge last month. He has said the makeup of juries was a legitimate sore point for defense lawyers and he would make the issue a priority.