The incident happened in Dynevor Road near Stoke Newington High Street just before 12.20am today (August 5).
Officers and London Ambulance Service crews attended and found a man who had been shot.
Stoke Newington High Street A10 closed after shooting: Live
He was pronouncded dead shortly after.
His next-of-kin have been informed and are being supported by specialist officers.
Formal identification and a post-mortem examination will take place in due course.
No arrests have been made at this stage.
Detective Chief Superintendent Brittany Clarke, who leads policing for the area, said:
“Our team of detectives and forensic specialists are working at pace to establish the full circumstances that led to the tragic death of this man.
“We understand this incident will cause concern within the Stoke Newington community, however we do believe this to be an isolated incident at this stage of the investigation with no wider risk to the general public.
“Residents can expect to see an increased police presence in the area, along with a crime scene, as we carry out our enquiries.
“We thank them for their patience and co-operation at this time.
“We urge anyone who witnessed the incident, or who has any information that could assist us, to come forward as soon as possible.”
Anyone who can help is asked to call police on 101, quoting CAD 108/5AUG.
Information can also be provided anonymously to Crimestoppers on 0800 555 111.
Dynevor Road and parts of Stoke Newington High Street remain closed at this stage.
