Police say Detective Patrick Finucane, 54, was found unresponsive in an apartment complex on South Wells just before 10:15 p.m.
Police will conduct an investigation but say the death does not appear to be suspicious in nature.
A police spokesperson released the following statement:
"Detective Finucane was a respected and dedicated member of the Chicago Police Department for 30 years, working tirelessly for both the city of Chicago and on behalf of the Chicago Police Memorial Foundation. We extend our sincere condolences to his family, friends and colleagues during this difficult time."
The spokesperson added that Finucane was known for his sense of humor and will be missed.