Police Superintendent Garry McCarthy and Mayor Rahm Emanuel attended the ceremony.
This is the first class of detectives to graduate since January 2008.
"You have an opportunity, a great opportunity to make a difference every single day. Do not lose faith when you get frustrated," McCarthy said.
Ten military veterans were among those who earned the rank.
The group joins more than 850 current detectives.
The new detectives will prepare for their new assignments Sunday with the Bureau of Detectives command staff and supervisors leading the orientation.
It was set to begin at 10 a.m. Sunday at Area Central Police Headquarters on South Wentworth.
Chicago police solve far fewer than half the city's murders and only a fraction of shootings.