The union, National Nurses United, made the announcement late Wednesday night after contract talks broke off despite the involvement of a federal mediator.
The strike will begin at 7 a.m. and last a full 24 hours.
"We've never had to strike at the University of Chicago, and we've been unionized since 1960; this is a big history for us," said Helen Bernard, ICU nurse.
In anticipation of the strike, University of Chicago Medical Center went on a full bypass late Wednesday night, asking ambulances to take patients to other hospitals
RELATED: University of Chicago Medical Center moves patients to other hospitals in anticipation for nurses' strike
Vice President of Patient Care Services Debi Albert called the strike "reckless and irresponsible."
"It's impacting our patients directly,' Albert said. "As we speak, we are in emergency management mode, preparing for this. We have had to bring in relief nurses."
Although the nurses have agreed to a 24-hour strike, which means they'd return to work Saturday morning at 7 a.m., hospital officials said replacement nurses needed a five-day guarantee to work through Tuesday. Hospital officials said union nurses will be allowed to return to work on Wednesday, September 25.
Members of the union's negotiating team criticized the move and called it a lockout.
"I call that reckless and irresponsible on the hospital's part," said Pam Valentine, University of Chicago registered nurse. She called it a "four day lockout."
University of Chicago Medical Center's contract with the National Nurses Union expired in April. Staffing, or lack of it, is a key issue.
"The nursing staff is being stretched to the limits and they have great concerns about the care they are able to provide," said Valentine, a nurse and a member of the negations team.
As an example, union leaders say nurses have filed 1,700 "Assignment Despite Objection" complaints during an 18-month period. When they file a complaint, the nurse must tell their supervisor that the shift is "suboptimal or unsafe," according to the report document.
"People don't do it because it was a bad day. They do it when they feel it was a dangerous day," said Marti Smith, lead negotiator for National Nurses United.
Albert said the union rejected a proposal that dealt with staffing. A proposal she called "very generous." But union leaders said the proposal only addressed the day shifts and not the night shifts.
Because of nurse strikes in dozens of hospitals in California, Arizona, and Florida, University of Chicago Medical Center has been able to retain fewer replacement nurses than they initially planned for.
Hospital officials said the medical center is now on full bypass, and is asking ambulances to take patients to other hospitals in the area. The hospital has put both its pediatric and adult emergency departments on bypass, put its Level 1 pediatric and adult trauma programs on diversion, limited transfers from community hospitals, temporarily closed some inpatient units, rescheduled some elective procedures, and transferred patients on a case-by-case basis to other hospitals in preparation for the strike.
"Until the nurses I know come back, I won't be coming back until they come back," said Kendra Rivers, patient.
"We're disheartened that we had to get to this point," said Sharon O'Keefe, University of Chicago Medical Center President. "We worked long and hard negotiating with the help of a federal mediator and had hoped union leadership would meet us half way. We now have to focus our efforts on safely operating our hospitals and caring for the patients who depend on us."
About 2,200 nurses will strike Friday from three hospitals in Hyde Park: Center for Care and Discovery, Mitchell Hospital and Comer Children's Hospital. Four outpatient clinics are also impacted: UChicago Medicine - Orland Park, UChicago Medicine - South Loop, and UChicago Medicine's South Shore Senior Center.
No new contract talks are scheduled before Friday.
Nationwide, nurses are striking in California, Arizona and Florida, and starting Friday, Chicago. And replacement nurses - from across the country - will be working on the South Side.
"You ship them all in. They don't care about me," patient Kendra Rivers said about the replacement nurses. "They don't care about how I'm feeling. Why would they care? They are not going to be here much longer...we hope."