The strike kicked off at about 6 a.m. as many began marching with picket signs outside of the hospital.
Workers with the National Union of Healthcare said they've been in negotiations with the hospital for more than a year over issues concerning short staffing and other problems that may hinder patient care.
Respiratory technician Noemi Aguirre said one sticking point deals with patient care committees, which are set up by union workers so they have a voice in patient care.
"They do not want us to have patient care committees," Aguirre said. "We feel because we're the No. 1 bedside personnel, that we know what is best and at least we can have some input in helping these people cope with whatever illnesses they're trying to cope with."
The union has also accused the hospital of unfair labor practices. Aguirre said one such practice surrounds staffing ratios.
"We have a lot of units where we are just plain short staffed," she said. "They haven't addressed those issues for us, and we feel we've been trying to bring those up in bargaining and for the last 14 months, we have been unsuccessful in getting them to see how important it is to us."
The hospital's director of human resources Matt Mcelaith said the institution is just focusing on delivering the kind of patient care they are known for.
"USC has a wonderful reputation for providing excellent care. We always have and we always will, and so our focus everyday is delivering exceptional patient care. We've done that before and we will continue to do that. Anything we can do to ensure we deliver great care is really what we're focused on," Mcelaith said.
The strike was scheduled to end at 6 p.m. Wednesday.