A burglar raided 70-year-old Sylvia Mulligan's home in Harcourt Close, Bessacarr, three weeks after her husband Anthony, 79, died there.
The crook broke into the bungalow last Sunday afternoon, stealing jewellery, Mr Mulligan's wallet, cash, a pocket watch and some rare coins.
The burglar moved Mr Mulligan's ashes from a bag which was then used to carry the stolen items from the property.
A South Yorkshire Police spokeswoman said: "It was reported to police that on Sunday, June 4, a bungalow on Harcourt Close, Doncaster, was broken into and a number of items including jewellery were stolen.
"Damage was also caused to two windows, the patio door and garden shed at the property during the reported burglary.
"Officers are currently investigating the incident and reviewing CCTV from the property.
"If you witnessed the reported burglary or saw any suspicious activity in the area, please contact the police.”
Call South Yorkshire Police on 101 or Crimestoppers on 0800 555111.