Emergency services were called to a block of flats in Atholl Street after a report that the floor collapsed into the building's basement.
Police said the woman was rescued from the basement and is understood to have sustained minor injuries.
Residents from the block of flats have been evacuated while a structural assessment is carried out.
Atholl Street is closed between Kinnoull Street and North Methven Street.
Five fire engines including the heavy rescue unit attended as well as police, ambulances and the Tayside trauma team.
A Scottish Ambulance Service spokesman said: "We received a call at 07:24 hours today to attend an incident at an address on Atholl Street, Perth.
"We dispatched one ambulance, our special operations response team, two managers and a trauma team.
"One female patient was taken to Perth Royal Infirmary."
A 25-year-old woman has been taken to hospital after a floor collapsed in a common close in Perth.