The incident took place on the R108 in St Margaret's at approximately 11.45am today.
The cyclist, a man in his 40’s was fatally injured and pronounced dead at the scene.
The male driver of the car was treated for non-life threatening injuries by ambulance services at scene.
The road is currently closed as Garda Forensic Collision Investigators conduct their examination, with local diversions in place.
Gardaí are appealing for anyone with information, particularly any road users who may have witnessed the collision or have dash-cam footage, to contact them at Dublin Airport Garda Station on 01 666 4950, the Garda Confidential Line on 1800 666 111 or any Garda station.