The collision, which involved a Peugeot 807 and Land Rover Discovery, happened on Andover Road North just before 8am this morning.
The road has been closed while emergency services attended.
Despite best efforts, the pedestrian, an 81-year-old man from Winchester, was sadly pronounced dead.
His next of kin have been informed and are being supported by specialist officers.
Officers investigating are keen to speak with anyone who may have witnessed the collision.
Maybe you have a dash cam and captured footage of the pedestrian in the lead up to the collision?
Anyone with information can call 101, quoting reference 129 of today’s date. Alternatively, you can call Crimestoppers anonymously on 0800 555 111.