South Yorkshire Police said a 39-year-old woman had been arrested in connection with the death and taken into custody.
Emergency services were called to a property in Cedric Crescent, a residential street in Thurcroft, just before 8.50pm on Wednesday.
A woman was found in cardiac arrest and was given emergency treatment by paramedics at the scene, but was pronounced dead a short time later.
The area remained cordoned off late on Wednesday as investigators sought to establish the circumstances around the woman’s death.
Officers appealed for anyone with information to come forward and call 101 or contact Crimestoppers anonymously on 0800 555111, quoting incident number 943 of 13 February 2019.