South Yorkshire Police said a woman called at a house in Fernhurst Road, Wheatley Hills, and was allowed inside for a cup of tea.
While she was in the house, belonging to a 76-year-old woman, a younger man who is thought to have been between 18 and 20, also called at the property.
Shortly after they left it was discovered that a purse had been taken from the house.
The woman who called at the property was wearing a black leather jacket and blue denim jeans or leggings.
The man had light-coloured hair and was wearing a white cap. He also had a bicycle with him.
Anyone with information should call South Yorkshire Police on 101.