The Chicago Tribune/WGN TV poll of 600 registered voters finds 40 percent of them approve of the job Blagojevich is doing as governor. That's down from 55 percent in February.
At the same time, the number of people who disapprove has risen to 36 percent, up from 27 percent in February.
The decline follows months of fighting between the governor and a wide range of political opponents.
The poll was conducted May 21 to the May 24. It has an error margin of four percentage points.