The body of a 55-year-old woman has been found at a flat in Camden, police said.
Officers were called to Bray, Fellows Road, north west London, at 10.30am on Friday after paramedics reported a woman had been discovered with stab injuries.
The victim was pronounced dead at the scene.
Scotland Yard said a murder investigation had been launched, and that detectives were keeping an “open mind” about the motive.
No arrests have been made and the woman’s next of kin have been informed.
A post-mortem examination will be held on Monday, police added.
Anyone with information is asked to call police on 0208 785 8244 or Crimestoppers anonymously on 0800 555111.