The woman, who was in her late 40s, was hit by a car on the N71.
It happened near Shepperton Lake, between Leap and Skibbereen at around 1pm.
A woman in her late 50s who was driving the car wan't injured.
The woman's body has been taken to Cork University Hospital, where a post-mortem will take place.
A section of the road between Skibbereen and Rosscarbery has been closed for a technical examination of the scene, and diversions are in place.
Gardai are appealing for anyone with information to contact them at Clonakilty Garda Station on 023 - 8821570, the Garda Confidential Line 1800 666 111 or any Garda Station.