Emergency services responded to reports that a woman was stabbed at a home at Wood Duck Court in Langwarrin about 6.30am.
The yet-to-be-formally identified woman died at the scene.
Officers arrested a 63-year-old man at the home, who is known to the woman.
A crime scene has been established while detectives investigate to determine the circumstances surrounding the death.
Anyone who witnessed the incident, with dashcam/CCTV footage or information is urged to contact Crime Stoppers on 1800 333 000.