The zoo and parking lot will close at 3:00 p.m., when preparations for the exercise will begin. The drill is scheduled to run from 7p.m. to 9pm and more than 400 people are expected to participate in the drill.
A public safety advisory said a significant public safety personnel presence and simulated gunfire can be anticipated in the area.
The Chicago Police Department, Chicago Fire Department and Chicago Office of Emergency Management and Communications will take part in the field training exercise.
The drill is closed to the public.