Officers who arrived at the home in Everett, WA say they could hear the victim shouting: "You tried to cut my head off. You're going to jail."
Quite why the 43-year-old woman wanted to attack her spouse is unclear, but he told cops that that it had been dark in the room and when he turned on the light he saw his wife holding the saw.
The 36-year-old also said he'd been cut with a hatchet.
His wife told officers she grabbed the saw Friday night because an intruder escaped out her daughter's window.
But Sgt. Robert Goetz said a child lock prevented the window from opening more than a few inches, telling the Daily Herald: "There was no evidence there was an intruder."
She also told them she had been wounded on the arm, but police found no fresh marks, but they did find blood smeared on the woman's clothes, the carpet and walls inside the house.
A sawzall with blood on it was recovered from the bedroom floor, while a hatchet was discovered on an upper shelf in the kitchen, police said in court documents.
It was wet and appeared to have been washed, cops said.
Neither have been named, but the husband was apparently treated in hospital and released.
His wife meanwhile was held in jail, with bail set at $250,000.