Pinal County Sheriff Paul Babeu says 55-year-old Leanor Guitard, of Oracle, has been booked on a charge of negligent homicide.
Authorities say Guitard called 911 from her home just before 8:30 p.m. Saturday to report she had shot a woman who had stabbed her.
Deputies say they found Guitard kneeling over the victim, who was lying on the ground.
They say the victim, whose identity has not been released, died a short time later.
Deputies seized a .357 revolver allegedly used by Guitard.
Babeu says Guitard was extremely intoxicated and gave investigators conflicting information about the incident.
Detectives say Guitard showed no physical injuries and no knives were found around the victim.