A woman aged 40 has been charged with murder following the death of a three-month-old baby girl in West Croydon, the Metropolitan Police said.
She will appear before Bromley Magistrates Court on Monday.
Scotland Yard said officers were called by London Ambulance Service to a home in Croydon shortly before 12pm on Saturday.
The baby was found unresponsive and taken to hospital. She died about an hour later.
A statement from the Met Police said: “A woman arrested following the death of a baby girl aged three months has been charged with her murder.
“At this early stage, police are not looking for anyone else in connection with this investigation. The baby and the woman arrested were known to each other.”