CPS officials reported no major disruptions at schools as the illinois standards achievement test got underway Tuesday.
The ISAT is a multiday exam required of all students in grades three through eight.
Many teachers and parents claimed the testing was a waste of classroom time since the current version of the test will be phased out.
CPS officials had threatened to force boycotting teachers from the school building, but they were allowed to stay and teach students who did not take the ISAT.
At least 1500 students from 80 schools reportedly opted not to take the test.
Results of the ISAT feed into data required by the federal No Child Left Behind Act.