Chopper 7 was over the scene near West 23rd and South Halsted streets around 7:30 a.m.
Crews could be seen staging in a nearby Amazon facility's parking lot near the South Loop, Chinatown, and Pilsen neighborhoods.
Chicago police said the CPD Marine Unit found a man around 40-50 years old in the water.
The man was pronounced dead on the scene, and his name was not immediately released.
Area detectives are conducting a death investigation pending autopsy results.
Authorities did not immediately provide further information.
This is a developing story. Check back with ABC7 for updates.