The cyclist, local man in his 50s, was injured in a collision on Holgate Road in York at 7.15pm on Sunday evening.
He died in hospital on Monday afternoon.
A spokesman for the force said: "We are not yet in a position to release the identity of the man."
Officers were called to reports of a collision involving a cyclist and a parked car on Sunday, the road was closed for several hours following the incident for police investigations.
The victim was treated at the scene for serious head injuries and was taken by ambulance to Leeds General Infirmary.
North Yorkshire Police want to hear from anyone who witnessed the collision, or saw the cyclist involved.
He was riding a yellow cycle, and wearing a grey sports top, blue cargo trousers and a khaki baseball cap.
Police urge any witnesses who have not yet come forward to get in touch.
Please dial 101, press 1 and pass information to the force control room quoting reference 12190062550.