The marked cars were driving north in the 1900-block of South Western Avenue just after 2:15 a.m., when one hit the other in Little Village, police said.
Four officers were in one vehicle, and two were in the other, according to CPD.
Four officers are listed in good condition, and two are listed in fair condition.
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They were all taken to a local hospital.
No one else was injured, police said.
It was not immediately clear what led up to the crash.