Police were called to a property in Stamford Hill, N16, at 10.52am on Friday, 4 June to a report of a stabbing.
Officers attended. A man, believed to be in his 30s, was found with stab injuries.
He was treated at the scene by officers who carried out CPR before paramedics from London Ambulance Service (LAS) and London’s Air Ambulance arrived.
Despite the efforts of emergency services, the man died at the scene a short time later.
Enquiries are ongoing to notify his next of kin.
A 31-year-old woman has been arrested on suspicion of murder. She has been taken into custody.
Homicide detectives from the Met’s Specialist Crime Command have been informed.
A post-mortem examination will be carried out in due course.
A crime scene has been put in place. Enquiries continue.
The man and the woman are believed to be known to each other and officers are not looking for anyone else in connection with this incident at this time.