The station on the District line in Gale Street, Dagenham was closed at around 6.50am today (March 10).
Officers and London Ambulance Service crews attended and a woman was taken to hospital for further treatment.
She was pronounced dead shortly after.
Becontree Underground station was closed as the incident was dealt with, however, it has since reopened.
A spokesperson for British Transport Police said: “Officers were called to a report of a medical incident at around 6.50am today (10 March) at Becontree Underground Station.
“Officers attended alongside paramedics and a lady was taken to hospital sadly she was later pronounced dead.”
