Police said the pensioner was "very shaken" following the incident at 10.05am on Sunday April 2.
The robber struck as the pensioner was walking along a ginnel between Park Square and Fairfield Mount.
He approached her from behind and grabbed her handbag before running off.
The suspect is described as a thin white man with short hair.
Police Constable Alex Booth of Wakefield District Police said; "This has been a very frightening incident for the victim who has been left very shaken after what happened.
"If anyone was in the area on Sunday morning and may have seen anyone acting suspiciously, or who may have seen anyone matching the suspects description running from the scene
I would urge them to come forward. Our enquiries are ongoing."
Anyone with information is asked to contact police via 101 quoting 13170148895. Information can also be passed to Crimestoppers on 0800 555 111.