The City of Chicago Math League is sponsored by the Chicago Board of Education to encourage students to challenge themselves mathematically. Each year twenty-five schools compete over five contests (four "regular" contests plus a citywide finals held at IIT) to determine the city champion and to prepare for competition at the state level.

Each contest consists of a 20 question exam which must be completed in 50 minutes. Contests are administered at three sites; schools are assigned to sites based on their locations. Competition is divided into four grade level/topic areas: Algebra 1 (9th grade), Geometry (10th grade), Algebra 2 (11th grade), and Pre-Calculus (12th grade). An advanced student who has already completed the course for her grade level (for example, a sophomore who has already completed geometry) can take an "Accelerated" version of that contest, or can take a higher-level contest. As a result, there are eight levels of competition. At each regional meet, ribbons are awarded to the top three students in each category. After four meets, the top 30 students in each category, based on city-wide rankings, are invited to the city finals. Seven awards are then given in each category based on the results of the citywide finals.