Emergency services were called to the blaze in Mill Road near Brook Street at 5.45pm on January 11.
Part of the ground floor of a mid-terraced house had been damaged by fire.
Emergency services found a woman inside the home, who was pronounced dead at the scene.
Her next of kin have been informed but she has yet to be formally identified.
The cause of the fire is yet to be determined.
We have contacted London Fire Brigade for further information.
A spokesperson for Metropolitan Police said: “Police are investigating after an elderly woman was found dead following a fire at a house in Erith.
“Officers were called at 5.45pm on Saturday, 11 January and attended the scene at Mill Road, Erith, with London Fire Brigade.
“Part of the ground floor of a mid-terraced house had been damaged by fire. Sadly, an 86-year-old woman was pronounced dead at the scene.
“Her next of kin have been informed but she has yet to be formally identified.
“The cause of the fire is yet to be determined.”
A spokesperson London Ambulance Service said: “We were called at 5.39pm on Saturday 11 January to reports of a fire in Mill Road, Erith.
“We sent resources to the scene, including an ambulance crew, a paramedic in a fast response car, an incident response officer and members of our Hazardous Area Response Team (HART).
“The first of our crews arrived in six minutes.
“Our crews treated a woman at the scene. Sadly, despite the best efforts of emergency responders, she died.”