Burglars stole jewellery, cash and a DVD player from an 86-year-old woman in broad daylight.
The thieves broke into the victim's home in Spa Hill, Upper Norwood, on Saturday, June 14.
The burglary, which police said left the woman "extremely upset and distressed", occured between 10.15am and 11.05am.
Det Cons Asim Siddique, from Croydon police, said: "I'd urge anyone who was in the Spa Hill area on that Saturday morning and might have seen someone acting suspiciously to get in touch with us.
"Understandably, the victim is extremely upset and distressed about the ordeal. We are hopeful that somebody in the area might have seen something that could help us in our enquiries."
Anyone with information can contact Croydon police on 101 or call Crimestoppers anonymously on 0800 555 111.