The incident, which involved a BMW X1, happened at about 3.30pm on Friday on the B4398 at Carreghofa, south of Llanymynech.
The 63-year-old woman was pronounced dead at the scene.
Dyfed-Powys Police has launched an investigation into the crash and is appealing for witnesses to come forward.
A police spokesperson said: "A BMW X1 and a pedestrian were involved in the collision.
“Anyone travelling along this road, and witnessed the collision, is asked to contact PC Cross 609 at Newtown Police Station, either online at bit.ly/DPPReportOnline, by email at email@example.com, or by calling 101.
“If you are deaf, hard of hearing, or speech impaired text the non-emergency number on 07811311908.”
A Welsh Ambulance Service spokesperson said: "We were called at 3.17pm on Friday 06 November to reports of a road traffic collision involving a pedestrian in the Carreghofa area. We responded with one rapid response car, one emergency ambulance and the Wales Air Ambulance. No further details are available."