Cecile Cross, 83, died of smoke inhalation, Linn County Medical Examiner Don Linder said.
The house was gutted by the fire, which started Wednesday night.
Robert Shelton, 25, was in his room on the first-floor of the house when he noticed his electric blanket had caught fire. He tried to throw coffee and water on it to put it out.
``We were getting ready for bed'' when it happened, said Richard Urban, 58, Shelton's father.
Urban and Shelton lived in the home with Urban's wife, Ginger, and Cross, who was Ginger Urban's mother.
The Urbans and Shelton were taken to St. Luke's Hospital and released early Thursday morning.
Richard Urban said he went back in the house two or three times to get Cross out.
``The smoke was so overwhelming,'' he said. ``It takes the oxygen right out of you.''
Cross was found on the second-floor of the single family home. She was pronounced dead at a local hospital.
The family had been renting the home. They are staying in a hotel with the help of the Red Cross.