The 70 year-old was seriously injured in the road traffic accident, which happened around 2.55pm.
The incident happened on the westbound carriageway of the road when the lady was struck by a white Vauxhall Combo van.
The woman was taken to hospital for treatment to serious injuries and both stretches of Whitletts Road were closed for some time in order for an investigation to take place.
Inspector Greg Dinnie of Ayrshire Road Policing said: " I am looking for any witnesses, who have not already came forward, to call in and pass any information they may have in relation to this.
" I am particularly interested in speaking to any drivers of occupants of vehicles that were travelling in either direction on Whitletts Road near to the Tesco Supermarket at the time who may have witnessed the incident and may have dash-cam footage.
"Any information should be reported to Police Scotland by calling 101, quoting incident number 2038 of 14 November, 2019."
