Doctors determined she had a fractured pelvis.
"She's in some pain but in very good spirits," Drake said.
Mrs. Reagan was undergoing physical therapy but surgery won't be required, Drake said. It was not known how long she'll be hospitalized.
Mrs. Reagan apparently got up in middle of the night and fell after twisting on her leg at her home in Bel-Air.
Mrs. Reagan was hospitalized three days in February after a similar fall at the hillside home she shared with President Reagan after their White House years. He died June 5, 2004, after a 10-year battle with Alzheimer's disease.
It was initially feared Mrs. Reagan broke her hip in that February fall, but tests determined there was no fracture.
