Robyn Kathleen Gevas, 36, was arrested for the murder of 62-year-old Callie Joshua Evans, Sgt. Chase Haag said. Both are Napa residents.
Police responded around 10:30 p.m. to a report of a stabbing inside a home in the 2000 block of Euclid Avenue, Haag said.
Evans was stabbed multiple times, and died of his injuries at Queen of the Valley Medical Center in Napa, Haag said.
Napa County sheriff's Capt. Tracey Stuart said Evans was pronounced dead at 11:01 p.m.
Gevas was booked into Napa County Jail at 4 a.m. today, Haag said. The case is still under investigation.