The campus had been locked down for about an hour-and-a-half Friday afternoon but a university official says there were no reports of shots fired or any injuries.
As of 2 p.m. Friday officials say on the school's Web site that the university and Tampa police departments have investigated the area and students and staff can return to normal activities.
There's no word yet on whether there was actually an armed person on campus.
This is the second time in as many months that a gunman was reported on USF's campus, CBS Tampa affiliate WTSP reports. No suspects were found when a gunman was reported on campus back in June.
School spokeswoman Lara Wade said there were no immediate reports of shots fired or injuries and no word of anyone being taken into custody.
The school sent out a mobile emergency message at 12:31 p.m. to notify 55,000 people of the incident. Messages were also displayed on digital screens throughout campus.
Jon Catuccio, who works at the school, said that a little before noon someone said over a loudspeaker that a gunman had been reported at the bioscience building in the heart of campus and people should stay inside.
He said he got an e-mail with the same information and everyone was "kind of hanging out" and waiting to see what happens.
Student Lawrence Stawkowski, 24, saw three helicopters flying around and said an alarm went off every 15 minutes.
"I wasn't too afraid," he said. "I was just surprised, a little shocked."
Junior Lynn McPhearson, 21, said he had been in the Marshall Center for about an hour and could see the bioscience building from the window.
"You don't see people running around like it's mass chaos," he said.
McPhearson said a group of parents and students who had been on campus for orientation were also inside.
The late summer term at USF just ended, so there were fewer students than usual on campus, said Allyson Stanfill, 21, who was stuck inside a lab across the street from the bioscience building.