Police were called at 10.18pm on Thursday, 25 March to a residential address in Kent Street E13.
Officers attended with paramedics from the London Ambulance Service. A 76-year-old woman was found; she was pronounced dead at the scene.
Next of kin are aware. Formal identification awaits and a post-mortem examination will be scheduled in due course.
A man aged in his 30s was arrested at the scene on suspicion of murder. He remains in police custody.
It is believed the deceased and the man arrested were known to each other.
Enquiries into the circumstances continue.
A crime scene remains in place and detectives from Specialist Crime are investigating.
Anyone who has information that could help police should call 101 ref CAD 7896/25 Mar.
Alternatively tweet @MetCC, or to remain 100% anonymous contact the independent charity Crimestoppers on 0800 555 111.