The school remained closed through Wednesday as a precaution. Thursday morning, classes resumed for the 17,000 students.
The college, along with local police and the FBI are investigating the threat.
A school official suspects the threat may have been a copy-cat of the threats that shut down Saint Xavier University on the city's South Side.
Extra Chicago police officers and security personnel will be at Saint Xavier University Thursday as campus life returns to normal.
Last week, graffiti that threatened violence on April 14th forced the university to close. Police investigating the threat believe the danger has passed.
The school reopened Wednesday for meetings with teachers and staff and graduate classes. Undergraduates resumed their class schedules Thursday morning.