The victim, who is in her 80s, had gone outside of her property in St Francis Close, Crowthorne, at about 1pm on Wednesday, October 24, to check her postbox.
When she returned into the communal area and went into her property she was approached from behind by a man who pushed her to the floor and stole her purse.
The pensioner was taken to hospital for treatment.
The offender is described as being white, in his mid to late 30s, about 6ft, and of broad build. He was wearing a black jacket, jeans and trainers.
Investigating officer Det Con Alex Hillan, of Bracknell CID, said: "This was a cowardly assault on an elderly and vulnerable woman in her own home."
If you have any information, Det Con Hillan at Bracknell CID on 101 or, to remain anonymous, call Crimestoppers on 0800 555 111.